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1
Grant, Robyn A., Vicki Breakell, and Tony J. Prescott. "Whisker touch sensing guides locomotion in small, quadrupedal mammals." Proceedings of the Royal Society B: Biological Sciences 285, no. 1880 (2018): 20180592. http://dx.doi.org/10.1098/rspb.2018.0592.
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All small mammals have prominent facial whiskers that they employ as tactile sensors to guide navigation and foraging in complex habitats. Nocturnal, arboreal mammals tend to have the longest and most densely packed whiskers, and semi-aquatic mammals have the most sensitive. Here we present evidence to indicate that many small mammals use their whiskers to tactually guide safe foot positioning. Specifically, in 11, small, non-flying mammal species, we demonstrate that forepaw placement always falls within the ground contact zone of the whisker field and that forepaw width is always smaller than whisker span. We also demonstrate commonalities of whisker scanning movements (whisking) and elements of active control, associated with increasing contact with objects of interest, across multiple small mammal species that have previously only been shown in common laboratory animals. Overall, we propose that guiding locomotion, alongside environment exploration, is a common function of whisker touch sensing in small, quadrupedal mammals.
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Tóth, Anikó B., S. Kathleen Lyons, W. Andrew Barr, et al. "Reorganization of surviving mammal communities after the end-Pleistocene megafaunal extinction." Science 365, no. 6459 (2019): 1305–8. http://dx.doi.org/10.1126/science.aaw1605.
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Large mammals are at high risk of extinction globally. To understand the consequences of their demise for community assembly, we tracked community structure through the end-Pleistocene megafaunal extinction in North America. We decomposed the effects of biotic and abiotic factors by analyzing co-occurrence within the mutual ranges of species pairs. Although shifting climate drove an increase in niche overlap, co-occurrence decreased, signaling shifts in biotic interactions. Furthermore, the effect of abiotic factors on co-occurrence remained constant over time while the effect of biotic factors decreased. Biotic factors apparently played a key role in continental-scale community assembly before the extinctions. Specifically, large mammals likely promoted co-occurrence in the Pleistocene, and their loss contributed to the modern assembly pattern in which co-occurrence frequently falls below random expectations.
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Song, Xiaowei, and Benjamin Rusak. "Acute effects of light on body temperature and activity in Syrian hamsters: influence of circadian phase." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, no. 5 (2000): R1369—R1380. http://dx.doi.org/10.1152/ajpregu.2000.278.5.r1369.
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Light exposure at night causes an acute increase in human body temperature, which normally falls during the night. This change is largely attributable to the suppression by light of the nocturnal rise in melatonin levels. Little is known, however, about the effects of light on body temperature in nocturnally active mammals in which the nightly peak in melatonin secretion coincides with the circadian phase of elevated, rather than decreased, body temperature. We investigated the effects of a 1-h exposure to light on body temperature and activity of Syrian hamsters, Mesocricetus auratus, at two phases during the night and at two phases during the projected day. Brain or abdominal temperature was recorded continuously using implanted radio transmitters while locomotor activity was monitored simultaneously using a passive infrared movement detector. Responses to light exposure were strongly circadian phase dependent; light during the night caused elevations in both brain and core body temperature, whereas light during the projected day did not. Temperature increases at night could not be attributed solely to activity increases at the onset of light pulses, indicating a contribution from nonbehavioral mechanisms of thermogenesis. These results provide the first evidence for circadian modulation of acute temperature responses to light in a nocturnal mammal.
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Barry, John C., Michèle E. Morgan, Lawrence J. Flynn, Louis L. Jacobs, and Everett H. Lindsay. "Patterns of faunal turnover and diversity in the Siwalik Neogene record in relation to regional and global events." Paleontological Society Special Publications 6 (1992): 18. http://dx.doi.org/10.1017/s2475262200005785.
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The fluvial Neogene Siwalik formations of northern Pakistan contain one of the longest and richest sequences of terrestrial vertebrate faunas known. The complete sequence extends from ca. 18 Ma to 1 Ma, with the interval between 18 and 7 Ma being best sampled. Throughout this best known interval vertebrate remains are frequently abundant in channel fills and less common in large channel sands, levees, and paleosols. Although the abundance and quality of fossil preservation varies, all stratigraphic levels have some fossils and the record of most subintervals is good to excellent. As a consequence the patterns of faunal turnover and changes in diversity can be documented and analyzed for 0.5 my long subintervals.Thirteen orders of Siwalik mammals have been identified, with well sampled subintervals typically having 50 or more species. Despite the ordinal diversity, however, most Siwalik mammal species belong to just three orders: rodents, artiodactyls, and perissodactyls. Among the larger mammals, the bovids and equids are the most common and have the most species, while the murid and cricetid rodents dominate the small mammal assemblages. These Siwalik abundance and diversity patterns differ markedly from those of the Paleogene and are a result of Neogene radiations in these four families and extinction of Paleogene groups.Between 18 and 7 Ma species diversity varies considerably. Among artiodactyls and rodents the number of species first increases between 15 and 13 Ma and then falls after 12 Ma. Significant changes in relative abundance are also known, including an increase in the abundance of bovids between 16.5 and 15 Ma and a very abrupt increase of murids at 12 Ma.Data on stratigraphic ranges of rodents and artiodactyls show that faunal change in the Siwaliks was episodic, occurring as short intervals with high turnover, followed by longer periods with considerably less change. Maxima of first appearances occur at approximately 13.5 and 8.5 Ma, while maxima of last appearances come at 12.0, 9.5, and 8.0 Ma. It is thus apparent that in the Siwaliks increased extinction did not accompany or closely follow maxima of first appearances.Correlations of these faunal events to global climatic trends are ambiguous. However, it is apparent that the middle Miocene diversification of Siwalik faunas occurred during a period of global cooling, while the late Miocene decline in diversity preceded a second episode of cooling and increasing aridity.
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Henrikson, L. Suzann. "Bison Heights: A Late Holocene Bison Kill Site on Idaho's Snake River Plain." North American Archaeologist 26, no. 4 (2005): 333–55. http://dx.doi.org/10.2190/34wt-5uxv-lukm-y3n3.
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Recent excavations at a narrow draw in close proximity to Tomcat Cave, one of Idaho's cold storage caves, exposed a concentration of charred mammal bones and a rock lined hearth in association with an elaborate series of rock alignments. Much of the long bone falls within the bovid size range (bison) and appears to be the byproduct of stone boiling or bone soup making. Radiocarbon dates from the hearth, and the presence of Intermountain ware ceramics, Rose Spring and Desert Side-notched points indicate use of the site during the very late Holocene. Analogous artifacts recovered from the mouth of Tomcat Cave indicate that hunting activities at Bison Heights and use of the cave likely coincided. The rock features at the site and those documented elsewhere within the region indicate that narrow topographic features were used as procurement locales for big game. However, limited amount of bone recovered near these features indicates that only a small number of animals were acquired during single hunting events.
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ANDREYCHEV, A. "NEW METHODS FOR STUDYING THE ACTIVITY OF SEMIAQUATIC MAMMALS." Periódico Tchê Química 16, no. 32 (2019): 27–33. http://dx.doi.org/10.52571/ptq.v16.n32.2019.45_periodico32_pgs_27_33.pdf.
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A new method for studying the activity of semiaquatic mammals using digital portable voice recorders has been developed. Previously, actographs and night-vision devices were used to study semiaquatic mammals near their burrows. This method allows the mammal activity registration directly in the burrows. The use of voice recorders makes it possible to accurately determine whether the burrow system is inhabited or non-inhabited. In addition, it has become possible to identify the day-night time intervals during which the animals are the most or least active. The new method was tested on the Russian desman (Desmana moschata). Therefore, to identify the burrows in which the recorders were to be installed, the burrows were probed. A probe is a pole pointed at one end with a T-shaped handle at the other end. The researcher's task is to detect the entrance to the burrow, usually under water. And then the direction of the underground passage is determined by means of the probe. For this purpose, the ground is pierced to detect the hollows in the burrow with the probe starting from the burrow entrance (the probe falls through unevenly). At a distance of 2–3 meters from the burrow, in some cases largely depending on the burrow length, the ground is dug up above the burrow in the form of a small well, 10–15 cm in diameter. A digital voice recorder was placed vertically in this well, so that the microphone was directed down towards the burrow. Desman noises can be characterized as short series formed as a sequence of contiguous short peaks of 15–25 seconds with 5 second interruptions formed by regular waves of breathing and its movement noises. Desman noises differ by mean amplitude and duration on oscillograms. As a rule, the noise audibility ranges from 1 to 3 minutes.
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Reed, J. Z., P. J. Butler, and M. A. Fedak. "The metabolic characteristics of the locomotory muscles of grey seals (Halichoerus grypus), harbour seals (Phoca vitulina) and Antarctic fur seals (Arctocephalus gazella)." Journal of Experimental Biology 194, no. 1 (1994): 33–46. http://dx.doi.org/10.1242/jeb.194.1.33.
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It is not known precisely how marine mammals are able to maintain muscle function during active swimming in breath-hold dives, when ventilation stops and heart rate falls. Examination of muscle biochemistry and histochemistry can provide information on the relative importance of different metabolic pathways, the contractile potential of the muscle fibres, the oxygen storage capacity of the muscle and the capillary distribution in these animals. In this study, samples of locomotory muscle were taken from wild grey seals (Halichoerus grypus), harbour seals (Phoca vitulina) and Antarctic fur seals (Arctocephalus gazella); Wistar rat muscle was analysed for comparative purposes. Activities of citrate synthase and beta-hydroxyacyl CoA dehydrogenase were higher in the harbour seal muscle than in the grey seal muscle, suggesting that harbour seals have a greater aerobic capacity. Both phocid muscles had a greater reliance on fatty acid oxidation than the fur seal or rat muscles. The myoglobin data demonstrate that the grey seals have the highest oxygen storage capacity of the three pinniped species, which correlates with their greater diving ability. Myoglobin levels were higher in all three pinniped species than in the Wistar rat. The fibre type compositions suggest that the muscles from the fur seals have higher glycolytic capacities than those of the phocid seals [fur seal pectoralis, 7% slow-twitch oxidative fibres (SO), 25% fast-twitch oxidative glycolytic fibres (FOG), 68% fast-twitch glycolytic fibres (FG); grey seal 57% SO, 5% FOG, 38% FG; area per cents]. However, the pectoralis muscle of the fur seal, although the most glycolytic of the pinniped muscles studied, has the highest capillary density, which indicates a high capacity for fuel distribution. These results show that, while pinniped muscle has an increased oxygen storage potential compared with the muscle of a typical terrestrial mammal, there are no distinct adaptations for diving in the enzyme pathways or fibre type distributions of the pinniped muscle. However, the muscle characteristics of each species can be related to its diving behaviour and foraging strategy.
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Woods, Roseina, Samuel T. Turvey, Selina Brace, Ross D. E. MacPhee, and Ian Barnes. "Ancient DNA of the extinct Jamaican monkey Xenothrix reveals extreme insular change within a morphologically conservative radiation." Proceedings of the National Academy of Sciences 115, no. 50 (2018): 12769–74. http://dx.doi.org/10.1073/pnas.1808603115.
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The insular Caribbean until recently contained a diverse mammal fauna including four endemic platyrrhine primate species, all of which died out during the Holocene. Previous morphological studies have attempted to establish how these primates are related to fossil and extant platyrrhines, whether they represent ancient or recent colonists, and whether they constitute a monophyletic group. These efforts have generated multiple conflicting hypotheses, from close sister-taxon relationships with several different extant platyrrhines to derivation from a stem platyrrhine lineage outside the extant Neotropical radiation. This diversity of opinion reflects the fact that Caribbean primates were morphologically extremely unusual, displaying numerous autapomorphies and apparently derived conditions present across different platyrrhine clades. Here we report ancient DNA data for an extinct Caribbean primate: a limited-coverage entire mitochondrial genome and seven regions of nuclear genome for the most morphologically derived taxon, the Jamaican monkey Xenothrix mcgregori. We demonstrate that Xenothrix is part of the existing platyrrhine radiation rather than a late-surviving stem platyrrhine, despite its unusual adaptations, and falls within the species-rich but morphologically conservative titi monkey clade (Callicebinae) as sister to the newly recognized genus Cheracebus. These results are not congruent with previous morphology-based hypotheses and suggest that even morphologically conservative lineages can exhibit phenetic plasticity in novel environments like those found on islands. Xenothrix and Cheracebus diverged ca. 11 Ma, but primates have been present in the Caribbean since 17.5–18.5 Ma, indicating that Caribbean primate diversity was generated by multiple over-water colonizations.
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DONALD, PAUL F., HTIN HLA, LAY WIN, et al. "The distribution and conservation of Gurney’s Pitta Pitta gurneyi in Myanmar." Bird Conservation International 24, no. 3 (2014): 354–63. http://dx.doi.org/10.1017/s0959270913000518.
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SummaryFollowing a recent assessment of the distribution and habitat use of Gurney’s Pitta in Myanmar (Burma), further extensive surveys were undertaken in 2010, 2011 and 2012. These have extended the species’ known altitudinal limit to between 250 m and 300 m asl and its latitudinal limit to above 12.5°N, around 80 km north of the northernmost historical record, although the species was recorded far less frequently at higher altitudes and latitudes. Birds were recorded in a range of forested habitats, from intact primary forest to secondary and bamboo forest, with no significant difference between major forest types in the likelihood of occurrence. Niche envelope modelling (MaxEnt) suggested a total range size in Myanmar of 3,379 km2, and did not identify any potentially suitable areas in adjacent parts of Thailand. The species’ preference for warmer, wetter areas on flat ground, conditions ideal for growing oil palm and rubber, suggest that its distribution is likely to contract in the near future. The entire range of Gurney’s Pitta in Myanmar falls within the part of the country most suitable for commercial oil palm production, although the projected yields within its range are low to moderate. Field surveys found evidence of rapid recent deforestation and high levels of hunting and trapping in many parts of the region. The species’ range in Myanmar does not overlap with any protected areas. The protection of southern Myanmar’s biodiversity will require substantial investment by foreign conservation interests, sympathetic land-use planning and the strengthening of environment legislation. Protection of extensive tracts of lowland forest within the range of Gurney’s Pitta, particularly the proposed Lenya National Park and the adjacent Ngawun and Htaung Pru Reserve Forests, is urgently needed. Conserving these areas will also protect populations of other globally threatened bird and mammal species.
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RASMUSSEN, CORNELIA, BETTINA REICHENBACHER, OLAF LENZ, et al. "Middle–late Miocene palaeoenvironments, palynological data and a fossil fish Lagerstätte from the Central Kenya Rift (East Africa)." Geological Magazine 154, no. 1 (2015): 24–56. http://dx.doi.org/10.1017/s0016756815000849.
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AbstractThe Miocene epoch was a time of major change in the East African Rift System (EARS) as forest habitats were transformed into grasslands and hominids appeared in the landscape. Here we provide new sedimentological and palynological data on the middle–upper Miocene Ngorora Formation (Tugen Hills, Central Kenya Rift, EARS), together with clay mineral characterizations, mammal finds and a description of the Ngorora fish Lagerstätte. Furthermore, we introduce a revised age ofc. 13.3 Ma for the onset of the Ngorora Formation. The older part of the Ngorora Formation (c. 13.3–12 Ma) records low-energy settings of lakes, floodplains and palaeosols, and evidence of analcime indicates that lakes were alkaline. The palynomorph spectrum consists of tree pollen (Juniperus, Podocarpus), Euphorbiaceae pollen (Acalypha, Croton) and herbaceous pollen of Poaceae and Asteraceae, suggestive of wooded grasslands or grassy woodlands. Alkaline lakes, floodplains and palaeosols continue upsection (c. 12–9 Ma), but environmental fluctuations become more dynamic. Paucity of palynomorphs and the presence of an equid may point to progressively drier conditions. A total of about 500 articulated fish fossils were recovered from distinctive layers of almost all sections studied and represent different lineages of the Haplotilapiines (Pseudocrenilabrinae, Cichlidae). Some of the fish kills may be attributable to rapid water acidification and/or asphyxiation by episodic ash falls. Repeated instances of abrupt change in water depth in many sections are more likely to be due to synsedimentary tectonic activity of the Central Kenya Rift than to climatic variation. Overall, the preservation of the Ngorora fish Lagerstätte resulted from the interplay of tectonics, formation of alkaline lakes and explosive volcanism. As records of grasslands that pre-date late Miocene time are rare, our finding of middle Miocene (12–13 Ma) grassy savannah in the Central Kenya Rift is also relevant to models of human evolution in East Africa.
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Pedrosa, Elaine Pessoa, Carla Soraia Soares de Castro, and Fabiana Lopes Rocha. "Threats to the brown-throated three-toed sloth Bradypus variegatus Schinz, 1825 (Pilosa: Bradypodidae) in an urban environment in State of Paraíba, Brazil." Revista Brasileira de Gestão Ambiental e Sustentabilidade 8, no. 19 (2021): 1169–81. http://dx.doi.org/10.21438/rbgas(2021)081936.
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The brown-throated three-toed sloth Bradypus variegates Schinz, 1825 (Pilosa: Bradypodidae) is an arboreal mammal with wide distribution in the neotropical region. However, the presence of this species in urban environments has attracted attention due to the threats that this environment can offer to this species. In this context, the present study investigated the impacts over brown-throated three toed sloth’s population living in an urban area of Rio Tinto, Paraíba, as well as, analyze data from Wildlife Screening Center (Centro de Triagem de Animais Silvestres - CETAS) and the conservation units of Paraíba, to understanding threats and main factors that led individuals to these institutions. From 2011 to 2014 a sloth’s population was studied at João Pessoa Square in Rio Tinto. From 2010 to 2015 was analyzed data from CETAS, Guaribas Biological Reserve (GBR), Barra do Rio Mamanguape Environmental Protection Area (BRM-EPA) and Arruda Câmara Municipal Zoobotanical Park (AC-MZP).The place that most registered the receipt of sloths was CETAS (65.5%), followed by GBR (17.8%), AC-MZP (15%), and BRM-EPA (1.8%). Offspring were significantly more impacted than adults, because were recorded highest number of injured and dead individuals in CETAS. Offspring not survived also at João Pessoa Square in Rio Tinto (urban environment) until the reproductive phase, due to falls or the rejection of their mothers during parental care. The urbanized matrix causes changes in the parental care of the mother sloths, implying the early abandonment of their offspring. In addition, inadequate introductions of sloths at João Pessoa Square causing malnutrition in individuals due to the lack of insufficient nutrients available, and electric shocks caused by high voltage wires, resulting in death or limb amputation of adult sloths. To minimize these impacts, urban environments needs to be controlled, through tree pruning, prohibit the introductions of sloths and increase the diversity of plant species in this area.
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Jones, Kate E., Tim M. Blackburn, and Nick J. B. Isaac. "Can unified theories of biodiversity explain mammalian macroecological patterns?" Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1577 (2011): 2554–63. http://dx.doi.org/10.1098/rstb.2011.0119.
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The idea of a unifying theory of biodiversity linking the diverse array of macroecological patterns into a common theoretical framework is very appealing. We explore this idea to examine currently proposed unified theories of biodiversity (UTBs) and their predictions. Synthesizing the literature on the macroecological patterns of mammals, we critically evaluate the evidence to support these theories. We find general qualitative support for the UTBs' predictions within mammals, but rigorous testing is hampered by the types of data typically collected in studies of mammals. In particular, abundance is rarely estimated for entire mammalian communities or of individual species in multiple locations, reflecting the logistical challenges of studying wild mammal populations. By contrast, there are numerous macroecological patterns (especially allometric scaling relationships) that are extremely well characterized for mammals, but which fall outside the scope of current UTBs. We consider how these theories might be extended to explain mammalian biodiversity patterns more generally. Specifically, we suggest that UTBs need to incorporate the dimensions of geographical space, species' traits and time to reconcile theory with pattern.
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Groussaud, Pauline, Stephen J. Shankster, Mark S. Koylass, and Adrian M. Whatmore. "Molecular typing divides marine mammal strains of Brucella into at least three groups with distinct host preferences." Journal of Medical Microbiology 56, no. 11 (2007): 1512–18. http://dx.doi.org/10.1099/jmm.0.47330-0.
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In order to investigate the genetic relationships within Brucella isolated from marine mammals, two genome-based typing methods, variable number of tandem repeats (VNTR) typing and multilocus sequence analysis (MLSA), were applied to a selection of 74 marine mammal isolates. All isolates were examined by VNTR and data were compared with multilocus sequencing data from a subset of 48 of these. Marine mammal brucellae are distinct from classically recognized species by these methods and appear to correspond to three major genetic groups, which reflect distinct preferred hosts. One group contains isolates predominantly found in pinnipeds (seals) and corresponds to the previously proposed species ‘Brucella pinnipediae’. However, isolates corresponding to the previously proposed species ‘Brucella cetaceae’ fall into two distinct groups that appear to have different preferred cetacean hosts (porpoises and dolphins). Furthermore, these two groups appear less closely related to each other than either group is to ‘B. pinnipediae’ isolates. The groups identified by VNTR typing and MLSA are completely congruent. The relevance of these findings to current proposals to recognize two species of marine mammal Brucella is discussed.
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Hornbeck, Garry E., and Dan Soprovich. "Relative abundance of the Prairie Long-tailed Weasel (Mustela frenata longicauda) in southwestern Alberta." Canadian Field-Naturalist 127, no. 2 (2013): 131. http://dx.doi.org/10.22621/cfn.v127i2.1443.
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Prairie Long-tailed Weasels (Mustela frenata longicauda) were live-trapped during fall 2005, 2006, and 2007 at Pine Coulee Reservoir and during fall 2005, 2008, and 2010 at Twin Valley Reservoir in southwestern Alberta. Our objective was to estimate the relative abundance of the Long-tailed Weasel and to estimate the relative abundance of small mammal prey. Body size and capture rates are reported for Long-tailed Weasels, and we report capture rates of small mammals. Annual capture rates for Long-tailed Weasels at Pine Coulee Reservoir were 0.44, 0.41, and 0.50 individuals per 100 corrected trap-nights (0.42, 0.38, and 0.48 individuals/100 trap-nights) in 2005, 2006, and 2007, respectively. No Long-tailed Weasels were captured at Twin Valley Reservoir. The probability of capturing zero Long-tailed Weasels at Twin Valley Reservoir was very low, assuming a true capture probability equivalent to that observed at Pine Coulee Reservoir. Deer Mice (Peromyscus maniculatus) were the most abundant small mammals captured in both project areas. Few shrews (Sorex spp.) and voles (Microtus spp.) were captured in either area.
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Steinbeiser, C. M., C. A. Wawrzynowski, X. Ramos, and Z. H. Olson. "Scavenging and the ecology of fear: do animal carcasses create islands of risk on the landscape?" Canadian Journal of Zoology 96, no. 3 (2018): 229–36. http://dx.doi.org/10.1139/cjz-2016-0268.
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Many vertebrate scavengers function as predators in ecosystems, suggesting that the presence of scavengers and occurrence of predator effects may be intertwined near carcasses. We tested for risk effects near a series of experimentally placed carcasses by measuring small-mammal foraging in a before–after control–impact design. Validation efforts revealed low levels of food loss from stations due to human error and invertebrate foraging, and habituation to stations occurred after 2 weeks. Increased perceived predation risk by small mammals relative to controls occurred in three of seven trials. The effect was observed across tested carcass types (beaver, Castor canadensis Kuhl, 1820; white-tailed deer, Odocoileus virginianus (Zimmermann, 1780)) and seasons (summer and fall). However, small mammals also increased foraging relative to controls in two of seven trials, and foraging reached a ceiling in two other trials that prevented inference on a response. Taken together, our results suggest that scavenger recruitment to carcasses can in some instances create islands of risk for prey on the landscape, but the effect is not likely to be universal. Where small-mammal foraging does decrease, further work will be necessary to determine if risk effects cascade to adjacent trophic levels through enhanced seed and seedling survival.
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Patrikeev, Michael. "An annotated checklist of mammals of the Lake Meredith National Recreation Area, Texas, USA." Check List 11, no. 2 (2015): 1595. http://dx.doi.org/10.15560/11.2.1595.
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Mammals of Lake Meredith National Recreation Area (Hutchinson, Moore and Potter counties, Texas) were surveyed between March 2002 and October 2003 as a part of the larger inventory of vertebrate animals of this protected area. Both Sherman and Tomahawk traps were used to catch small and medium-size mammals (for a total 330 trap-nights). Pit-fall traps, gopher live traps, Trailmaster™ cameras, mist-nets (for bats), and spotlight surveys were also utilized. The study detected 29 (72.5%) of the 39 mammalian species previously confirmed for Lake Meredith, and provided confirmed records for four other species (Cryptotis parva, Notiosorex crawfordi, Dasypus novemcinctus, and Sciurus niger). Four additional species were recorded in the adjacent area. This manuscript compares the 2002–2003 study with the three mammal inventories previously undertaken in the area (Blair 1954; Killebrew 1979; Yancey et al. 1998).
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Hoffmann, Michael, Jerrold L. Belant, Janice S. Chanson, et al. "The changing fates of the world's mammals." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1578 (2011): 2598–610. http://dx.doi.org/10.1098/rstb.2011.0116.
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A recent complete assessment of the conservation status of 5487 mammal species demonstrated that at least one-fifth are at risk of extinction in the wild. We retrospectively identified genuine changes in extinction risk for mammals between 1996 and 2008 to calculate changes in the International Union for Conservation of Nature (IUCN) Red List Index (RLI). Species-level trends in the conservation status of mammalian diversity reveal that extinction risk in large-bodied species is increasing, and that the rate of deterioration has been most accelerated in the Indomalayan and Australasian realms. Expanding agriculture and hunting have been the main drivers of increased extinction risk in mammals. Site-based protection and management, legislation, and captive-breeding and reintroduction programmes have led to improvements in 24 species. We contextualize these changes, and explain why both deteriorations and improvements may be under-reported. Although this study highlights where conservation actions are leading to improvements, it fails to account for instances where conservation has prevented further deteriorations in the status of the world's mammals. The continued utility of the RLI is dependent on sustained investment to ensure repeated assessments of mammals over time and to facilitate future calculations of the RLI and measurement against global targets.
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Geiser, F. "Hibernation and Daily Torpor in Marsupials - a Review." Australian Journal of Zoology 42, no. 1 (1994): 1. http://dx.doi.org/10.1071/zo9940001.
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Most heterothermic marsupials appear to display one of the two patterns of torpor that have been described in placental mammals. During shallow, daily torpor body temperature (T(b)) falls for several hours from about 35-degrees-C to values between 11 and 28-degrees-C, depending on the species, and metabolic rates fall to about 10-60% of the basal metabolic rate (BMR). In contrast during deep and prolonged torpor (hibernation), T(b) falls to about 1-5-degrees-C, metabolic rates to about 2-6% of BMR and torpor bouts last for 5-23 days. Shallow, daily torpor has been observed in the opossums (Didelphidae), the carnivorous marsupials (Dasyuridae) and the small possums (Petauridae). Daily torpor may also occur in the numbat (Myrmecobiidae) and the marsupial mole (Notoryctidae). Deep and prolonged torpor (hibernation) has been observed in the pygmy possums (Burramyidae), feathertail glider (Acrobatidae) and Dromiciops australis (Microbiotheriidae). The patterns of torpor in marsupials are paralleled by those of monotremes, placentals and even birds. These similarities in torpor patterns provide some support to the hypothesis that torpor may be plesiomorphic. However, as endothermy and torpor in birds apparently has evolved separately from that in mammals and as torpor occurrence in mammals can change within only a few generations it appears more likely that torpor in endotherms is convergent.
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Rikha, A. S., E. L. Widiastuti, N. Nurcahyani, and M. Kanedi. "RECENT BIODIVERSITY IN ANAK KRAKATAU ISLAND." KnE Life Sciences 2, no. 1 (2015): 245. http://dx.doi.org/10.18502/kls.v2i1.151.
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<p>Anak Krakatau Island is a volcanic island in the Krakatau preservation complex. With its regular explosions, ranging from2 80 times/day in the year 2013, it was expected that the biodiversity would experience many changes. In orderto determine the recent condition of the biodiversity, especially animal inhabitants, a survey was conducted within the island in June, 2013. The survey was made for mammal, bird, reptile, and invertebrate(ground, aerial, and arboreal) diversity. For mammals, 10 live traps were used along 100 m of line transect, birds and reptiles were adopted faced encountered method, while the invertebrate survey was conducted with visual techniques with a sweep net, pit-fall traps, and light traps. The result from the inventory (especially invertebrate) was followed by determining the diversity and dominance of species. Relative abundancewas also determined for mammals only. The survey indicated that there was 1 species of mammal with 20% of relativeabundance, 13 species of birds within 11 families, 2 species of reptiles, 58 species of insect, and 10 species of non-insect invertebrates, which consisted of 6 species of Araneae, 2 species of Scorpiones, 2 species of Chilopoda. The diversity indexfor insects was 4.011 with Bothriamyrmex sp. as subdominantin which its index of 2.86, and index for non-insects was 2.079. The result also was compared with the other 3 islands of the Krakatau complex and data collected in the last 10 years.</p><p><br /><strong>Keywords</strong>: Anak Krakatau, volcanic, biodiversity</p>
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Suárez, E., J. Stallings, and L. Suárez. "Small-mammal hunting by two ethnic groups in north-western Ecuador." Oryx 29, no. 1 (1995): 35–42. http://dx.doi.org/10.1017/s0030605300020858.
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A small-mammal hunting study was carried out in north-western Ecuador from October 1992 to October 1993, employing interview and trapping methods to document rodent and marsupial hunting by Chachi Indian and Afroecuadorian families. Based on 109 family interviews in 28 communities, it was determined that log-fall traps were used around family gardens and along forest trails. Afroecuadorian families used more than twice the number of traps than Chachis and trap lines of both ethnic groups were left open for approximately 6 days per trapping session. Chachi families left trap lines closed twice sas long as Afroecuadorian families. There were 857 individuals of seven rodent and four marsupial species trapped during the study, with Proechimys semispinosus representing more than 50 per cent of the small mammals trapped.
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Wilson, B. A., and G. R. Friend. "Responses of Australian Mammals to Disturbance: A Review." Australian Mammalogy 21, no. 1 (1999): 87. http://dx.doi.org/10.1071/am99087.
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The Australian native mammal fauna has evolved in an environment where 'natural' or endogenous disturbance is ongoing and widespread, be it fire, flood, drought or cyclones. Since European settlement, however, the type, scale, frequency and intensity of disturbance has changed and added a new suite of exogenous impacts including introduced predators and herbivores, vegetation clearance, habitat fragmentation, altered fire regimes, grazing and timber harvesting. This has presented novel and significant adaptive challenges to native mammals over a compressed time-scale, resulting in major extinctions, population declines and disruption to community structure. In this paper we examine the ecology of Australian mammals in the context of these new disturbances, and compare the response patterns observed, and assess the processes operating. In general, Australian mammalian successional patterns are closely tied to vegetation regeneration, which is related to the degree of disruption. Disturbances such as predation do not fall within this pattern. Mammalian successional states vary between different disturbance types within an ecosystem, depending on the critical elements of vegetation structure and composition. Landscape and climatic factors also affect successional patterns and need to be further investigated.
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Pagoulatos, Peter. "Late Archaic Settlement Patterns of the Inner Coastal Plain of New Jersey." North American Archaeologist 24, no. 2 (2003): 85–127. http://dx.doi.org/10.2190/86c1-fdtw-663y-2t9j.
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Late Archaic (4000-1000 B.C.) settlement patterns in the State of New Jersey are poorly understood in comparison with other parts of the Northeastern United States. This study is designed to evaluate current settlement pattern data, using logistical models of land use, against available archaeological data. Current data indicate that Late Archaic populations exhibited a complex series of seasonal movements, based upon seasonal availability of resources and highly ritualized cremation burial behavior. Late Archaic groups coalesced in riverine zones of the Inner Coastal Plain in the fall, as economic activities oriented toward nut harvesting, mammal hunting, and fishing, coincided with increasingly formal and complex cremation burial ritual; settlement systems at this time broadly correspond to collectors. With the completion of the fall season food harvesting and ritual cycle, mobile groups most resembling foragers dispersed into upland zones in the winter months to hunt mammals and coastal zones in the spring and summer to procure aquatic-related resources. Regional climatic changes toward the end of the Late (Terminal) Archaic and the early portion of the Early Woodland (1200-500 B.C.) may have necessitated higher group mobility more typical of foragers and corresponding changes in cremation burial ritual.
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Geraci, Joseph R., Donald M. Anderson, Ralph J. Timperi, et al. "Humpback Whales (Megaptera novaeangliae) Fatally Poisoned by Dinoflagellate Toxin." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 11 (1989): 1895–98. http://dx.doi.org/10.1139/f89-238.
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During a 5–wk period beginning in late November, 1987, 14 humpback whales, Megaptera novaeangliae, died in Cape Cod Bay after eating Atlantic mackerel, Scomber scombrus, containing saxitoxin (STX), a dinoflagellate neurotoxin responsible for paralytic shellfish poisoning in humans. We propose a line of evidence to explain how whales, by virtue of their diving adaptations, may be particularly vulnerable to this systemic neurotoxin. Absence of STX in New England waters and shellfish during the episode suggests that the mackerel, representing the northern stock which spawns in the Gulf of St. Lawrence, accumulated the toxin there and delivered it to the Gulf of Maine and Cape Cod Bay in the fall of 1987. These findings challenge common perceptions of the manner in which planktonic toxins move through the food chain, and offer new insights into natural mortality and standings of marine mammals. It seems appropriate to search for STX and other phytotoxins when investigating marine mammal mortalities.
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Pavone, Ilja Richard. "Is Banning Enough? The Intricacy Inherent to Marine Mammal Conservation." German Law Journal 20, no. 05 (2019): 587–613. http://dx.doi.org/10.1017/glj.2019.52.
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AbstractDeclining populations of marine mammals have led to growing concern about their conservation. As a result, a series of specific conservation measures have been put in place (bans on hunting and trading, establishment of protected marine areas). Such rules, although restoring the populations of some species of marine mammals, have nevertheless failed to protect them from the most challenging threat to their survival: the bycatch of non-target species. Accordingly, this Article highlights gaps within fisheries law, clarifying the efficacy of existing norms on the protection of the most endangered marine species of marine mammals, with a particular focus on cetaceans, from over-exploitation.To this aim, the Article explores the peculiar norms developed by treaties of global and regional scope and the European Union (EU) with reference to specific species, including whales, seals, small cetaceans—referred to as direct protection. The Article then proceeds to an analysis of fisheries law that addresses, in an incidental manner, marine mammal protection—referred to as indirect protection.The Article is based on the assumption that measures simply banning hunting or fishing, as envisaged by wildlife law, must necessarily be complemented by fisheries law—that is, Inter-regime linkages. Paradoxically, indirect protection can have a major impact in terms of improvement of both fish welfare and conservation; the problem lies in the fact that current fisheries law fails to provide an adequate response to bycatch. This Article proposes methods to improve fisheries law and also discusses whether the emerging concept of fish welfare can be an asset if included in fisheries rules; the Article ultimately contends that welfare issues must necessarily be part of future legal developments.
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Carroll, Michael S., Jean-Charles Viemari, and Jan-Marino Ramirez. "Patterns of inspiratory phase-dependent activity in the in vitro respiratory network." Journal of Neurophysiology 109, no. 2 (2013): 285–95. http://dx.doi.org/10.1152/jn.00619.2012.
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Mechanistic descriptions of rhythmogenic neural networks have often relied on ball-and-stick diagrams, which define interactions between functional classes of cells assumed to be reasonably homogenous. Application of this formalism to networks underlying respiratory rhythm generation in mammals has produced increasingly intricate models that have generated significant insight, but the underlying assumption that individual cells within these network fall into distinct functional classes has not been rigorously tested. In the present study we used multiunit extracellular recording in the in vitro pre-Bötzinger complex to identify and characterize the rhythmic activity of 951 cells. Inspiratory phase-dependent activity was estimated for all cells, and the data set as a whole was analyzed with principal component analysis, nonlinear dimensionality reduction, and hierarchical clustering techniques. None of these techniques revealed categorically distinct functional cell classes, indicating instead that the behavior of these cells within the network falls along several continua of spiking behavior.
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Garden, Jenni G., Clive A. McAlpine, Hugh P. Possingham, and Darryl N. Jones. "Using multiple survey methods to detect terrestrial reptiles and mammals: what are the most successful and cost-efficient combinations?" Wildlife Research 34, no. 3 (2007): 218. http://dx.doi.org/10.1071/wr06111.
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The selection of methods for wildlife surveys is a decision that will influence the accuracy and comprehensiveness of survey outcomes. The choice of methods is commonly based on the species of interest, yet is often limited by the project budget. Although several studies have investigated the effectiveness of various survey techniques for detecting terrestrial mammal and reptile species, none have provided a quantitative analysis of the costs associated with different methods. We compare the detection success and cost efficiency of cage traps, Elliott traps, pit-fall traps, hair funnels, direct observation, and scat detection/analysis for detecting the occurrence of terrestrial reptile and small mammal species in urban bushland remnants of Brisbane City, Queensland, Australia. Cage traps and Elliott traps coupled with hair funnels were the most cost-effective methods for detecting the highest number of ground-dwelling mammal species. Pit-fall traps and direct observations were the most cost-effective methods for maximising the number of reptile species identified. All methods made a contribution to overall detection success by detecting at least one species not detected by any other method. This suggests that a combination of at least two complementary methods will provide the most successful and cost-efficient detection of reptile and mammal species in urban forest remnants. Future studies should explicitly test these findings and examine efficient trapping combinations across different habitat types and for other fauna groups.
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Barros, Renata C. H., Mary E. Zimmer, Luiz G. S. Branco, and William K. Milsom. "Hypoxic metabolic response of the golden-mantled ground squirrel." Journal of Applied Physiology 91, no. 2 (2001): 603–12. http://dx.doi.org/10.1152/jappl.2001.91.2.603.
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We examined the magnitude of the hypoxic metabolic response in golden-mantled ground squirrels to determine whether the shift in thermoregulatory set point (Tset) and subsequent fall in body temperature (Tb) and metabolic rate observed in small mammals were greater in a species that routinely experiences hypoxic burrows and hibernates. We measured the effects of changing ambient temperature (Ta; 6–29°C) on metabolism (O2 consumption and CO2 production), Tb, ventilation, and heart rate in normoxia and hypoxia (7% O2). The magnitude of the hypoxia-induced falls in Tb and metabolism of the squirrels was larger than that of other rodents. Metabolic rate was not simply suppressed but was regulated to assist the initial fall in Tb and then acted to slow this fall and stabilize Tb at a new, lower level. When Ta was reduced during 7% O2, animals were able to maintain or elevate their metabolic rates, suggesting that O2 was not limiting. The slope of the relationship between temperature-corrected O2 consumption and Taextrapolated to a Tset in hypoxia equals the actual Tb. The data suggest that Tset was proportionately related to Ta in hypoxia and that there was a shift from increasing ventilation to increasing O2extraction as the primary strategy employed to meet increasing metabolic demands under hypoxia. The animals were neither hypothermic nor hypometabolic, as Tb and metabolic rate appeared to be tightly regulated at new but lower levels as a result of a coordinated hypoxic metabolic response.
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Fukushima, Toshihiko, Robert Siddall, Fabian Schwab, et al. "Inertial Tail Effects during Righting of Squirrels in Unexpected Falls: From Behavior to Robotics." Integrative and Comparative Biology 61, no. 2 (2021): 589–602. http://dx.doi.org/10.1093/icb/icab023.
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Abstract Arboreal mammals navigate a highly three dimensional and discontinuous habitat. Among arboreal mammals, squirrels demonstrate impressive agility. In a recent “viral” YouTube video, unsuspecting squirrels were mechanically catapulted off of a track, inducing an initially uncontrolled rotation of the body. Interestingly, they skillfully stabilized themselves using tail motion, which ultimately allowed the squirrels to land successfully. Here we analyze the mechanism by which the squirrels recover from large body angular rates. We analyzed from the video that squirrels first use their tail to help stabilizing their head to visually fix a landing site. Then the tail starts to rotate to help stabilizing the body, preparing themselves for landing. To analyze further the mechanism of this tail use during mid-air, we built a multibody squirrel model and showed the righting strategy based on body inertia moment changes and active angular momentum transfer between axes. To validate the hypothesized strategy, we made a squirrel-like robot and demonstrated a fall-stabilizing experiment. Our results demonstrate that a squirrel’s long tail, despite comprising just 3% of body mass, can inertially stabilize a rapidly rotating body. This research contributes to better understanding the importance of long tails for righting mechanisms in animals living in complex environments such as trees.
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Sazima, Ivan, and Cristina Sazima. "Cleaner birds: an overview for the Neotropics." Biota Neotropica 10, no. 4 (2010): 195–203. http://dx.doi.org/10.1590/s1676-06032010000400025.
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Several bird species feed on a variety of external parasites and epibionts, organic debris, dead and wounded tissue, clots and blood, and secretions from the body of other vertebrates (hosts or clients). We present an overview of so called cleaner birds from the Neotropics based on field records, literature, and photo survey. We found that 33 bird species in 16 families practice cleaning even if some of them do so very occasionally. The birds range from the Galápagos ground finch Geospiza fuliginosa to the widespread black vulture Coragyps atratus. Clients mostly are large herbivores such as capybaras, deer, and livestock, but also include medium-sized herbivores such as iguanas and tortoises, and carnivores such as boobies and seals - a few bird species associate with these latter marine mammals. No carnivorous terrestrial mammal client is recorded to date except for a domestic dog, from whose hair black vultures picked organic debris. Some clients adopt particular inviting postures while being cleaned, whereas others are indifferent or even disturbed by the activity of cleaner birds. Capybaras, giant tortoises, and iguanas are among the inviting clients, whereas boobies try to dislodge the 'vampire' finch Geospiza difficilis. Most of the Neotropical cleaner birds may be lumped in one broad category (omnivores that dwell in open areas and associate with large to medium-sized herbivores). A second, restricted category accommodates some species from Patagonia and the Galápagos Islands (omnivores that dwell in open areas and associate with carnivorous marine mammals, or seabirds and marine reptiles). Two still more restricted categories accommodate the following: 1) forest-dwelling cleaner birds; and 2) marine coastal cleaners. Additional records of Neotropical cleaner birds will mostly fall in the broad category.
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Lee, Michael S. Y. "Molecules, morphology, and the monophyly of diapsid reptiles." Contributions to Zoology 70, no. 1 (2001): 1–22. http://dx.doi.org/10.1163/18759866-07001001.
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The morphological and molecular evidence for higher-level reptile relationships is reassessed. A combined analysis of 176 osteological, 40 soft anatomical, and 2903 (1783 aligned) molecular characters in 28 amniote taxa yields the traditional reptile tree. Synapsids (including mammals) are the sister taxon to all other amniotes, including all extant reptiles. Turtles group with anapsid parareptiles and fall outside a monophyletic Diapsida. Within diapsids, squamates and Sphenodon form a monophyletic Lepidosauria, and crocodiles plus birds form a monophyletic Archosauria. This tree is identical to the tree strongly supported by the osteological data alone when fossils are included. In a combined analysis the strong osteological signal linking turtles with anapsids is sufficient to override a soft anatomical signal placing turtles next to a heterodox archosaur-mammal clade, and a weaker molecular signal linking turtles with archosaurs. However, the turtle-archosaur clade cannot be statistically rejected. When fossils are ignored, the signal in the osteological data set disappears and, in a combined analysis of morphology and molecules, the molecular (turtle-archosaur) signal prevails. These results highlight the importance of fossils, not just in osteological studies, but even in “combined” analyses where they cannot be scored for the majority of characters (soft anatomy and molecules). Although the total number of molecular traits (2903) is much greater than the total number of morphological taits (216), when only characters informative at the relevant levels are considered, the two data sets are approximately equal in size. The partition homogeneity test yields unreliable results unless uninformative (invariant and autapomorphic) characters are excluded. Analyses of the mitochondrial data suggest that recent evidence from nuclear genes for a heterodox turtlecrocodile clade (excluding birds) might be an artefact of inadequate sampling of a diverse outgroup (mammals) and thus, problems with rooting the reptile tree.
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Lyman, R. Lee. "Taxonomic composition and body-mass distribution in the terminal Pleistocene mammalian fauna from the Marmes site, southeastern Washington State, U.S.A." Paleobiology 39, no. 3 (2013): 345–59. http://dx.doi.org/10.1666/12039.
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Mean adult body mass of mammal taxa is a fundamental ecological variable. Variability in the distributions of body masses of a mammal fauna suggest variability in habitat structure. Mammal remains from the Marmes archaeological site in southeastern Washington State date between 13,200 and 10,400 b.p., during the Pleistocene–Holocene transition (PHT). Known environmental history prompts the expectations that the Marmes PHT mammal remains should represent greater species richness and a larger array of body-mass sizes than modern faunas in the Marmes locale and in open shrub-steppe habitats, and lower species richness and a smaller array of body-mass sizes than modern faunas in closed forest habitats; species richness and the array of body-mass sizes should be similar to that for a mixed habitat of cool shrub-steppe with scattered conifers. The Marmes PHT cenogram meets these expectations. Body-mass clumps displayed by the Marmes PHT mammal fauna fall between those of closed forests and open shrub-steppe habitats in terms of clump richness and breadth, and in terms of gap width. Marmes PHT body-mass clumps are very similar to those for the mixed habitat. Cenograms and body-mass clumps confirm conclusions drawn 40 years ago that the Marmes PHT habitat was much like that of today but cooler and with more plant biomass and greater structural diversity than today.
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Nameer, P. O. "A checklist of mammals of Kerala, India." Journal of Threatened Taxa 7, no. 13 (2015): 7971. http://dx.doi.org/10.11609/jott.2000.7.13.7961-7972.
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<p>A checklist of mammals of Kerala State is presented in this paper. Accepted English names, scientific binomen, prevalent vernacular names in Malayalam, IUCN conservation status, endemism, Indian Wildlife (Protection) Act schedules, and the appendices in the CITES, pertaining to the mammals of Kerala are also given. The State of Kerala has 118 species of mammals, 15 of which are endemic to Western Ghats, and 29 species fall under the various threatened categories of IUCN. </p><div> </div>
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Nameer, P. O. "A checklist of mammals of Kerala, India." Journal of Threatened Taxa 7, no. 13 (2015): 7971. http://dx.doi.org/10.11609/jott.2000.7.13.7971-7982.
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<p>A checklist of mammals of Kerala State is presented in this paper. Accepted English names, scientific binomen, prevalent vernacular names in Malayalam, IUCN conservation status, endemism, Indian Wildlife (Protection) Act schedules, and the appendices in the CITES, pertaining to the mammals of Kerala are also given. The State of Kerala has 118 species of mammals, 15 of which are endemic to Western Ghats, and 29 species fall under the various threatened categories of IUCN. </p><div> </div>
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Fuda, Rebecca K., Sadie J. Ryan, Jonathan B. Cohen, Joel Hartter, and Jacqueline L. Frair. "Assessing the impacts of oil exploration and restoration on mammals in Murchison Falls Conservation Area, Uganda." African Journal of Ecology 56, no. 4 (2018): 804–17. http://dx.doi.org/10.1111/aje.12568.
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Schadt, J. C., and J. Ludbrook. "Hemodynamic and neurohumoral responses to acute hypovolemia in conscious mammals." American Journal of Physiology-Heart and Circulatory Physiology 260, no. 2 (1991): H305—H318. http://dx.doi.org/10.1152/ajpheart.1991.260.2.h305.
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In conscious mammals including humans, the neurohumoral and hemodynamic responses to progressive acute hypovolemia have two distinct phases. There is an initial arterial baroreceptor-mediated phase in which the fall in cardiac output is nearly matched by a sympathetically mediated increase in peripheral resistance so that arterial pressure is maintained near normal levels. In most species, adrenal catecholamines and vasopressin contribute little to this phase. Increased renin release appears to augment the sympathetically mediated vasoconstriction. When blood volume has fallen by a critical amount (approximately 30%), a second phase develops abruptly. This phase is characterized by withdrawal of sympathetic vasoconstrictor drive, relative or absolute bradycardia, an increase in release of adrenal catecholamines and vasopressin, and a profound fall in arterial pressure. In rabbits and rats the signal that initiates this phase appears to travel in cardiopulmonary afferents. In dogs and humans its origin is unknown. Central opioidergic and serotonergic mechanisms may be involved.
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Hart, Terese B. "Seed, seedling and sub-canopy survival in monodominant and mixed forests of the Ituri Forest, Africa." Journal of Tropical Ecology 11, no. 3 (1995): 443–59. http://dx.doi.org/10.1017/s0266467400008919.
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ABSTRACTThe central Ituri Forest of Zaïre is characterized by monodominant stands of Gilbert-iodendron dewevrei (mbau forest) within a matrix of mixed forest where Julbernardia seretii is subdominant. Both species produce supra-annual, synchronous (mast) seed crops. The relationship of mast seed production to monodominance for the two tree species was evaluated by investigating: (1) the relationship between seed density and seed survival, (2) the relative impact of mammal versus insect seed predators in high and low seed density areas, and (3) post-germination survival in the understorey. For the latter, tagged seedlings were monitored over 10 years and both species were censused in different understorey size classes. Percentage seed survival was significantly greater for Julbernardia (but not for Gilbertiodendron) in areas of high conspecific seed density. Generalist fruit- and seed-eating mammals were the principal predators on seeds of both species when removed to areas without seed-fall. In mast areas high seed densities appeared to satiate mammalian seed predators but not the specialized beetle seed predators that were the major cause of seed destruction. Gilbertiodendron seedlings survived longer in the forest understorey than did seedlings of Julbernardia. Furthermore, Gilbertiodendron made up a greater proportion of the larger subcanopy size classes in monodominant forest than did Julbernardia in mixed forests. These results suggest that, irrespective of mortality to seeds, the ability to persist in the understorey may confer on Gilbertiodendron a greater probability of reaching and dominating the canopy.
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Gallo, Travis, Lani T. Stinson, and Liba Pejchar. "Mitigation for energy development fails to mimic natural disturbance for birds and mammals." Biological Conservation 212 (August 2017): 39–47. http://dx.doi.org/10.1016/j.biocon.2017.05.023.
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Abrahams, S., L. Greenwald, and D. L. Stetson. "Contribution of renal medullary mitochondrial density to urinary concentrating ability in mammals." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 261, no. 3 (1991): R719—R726. http://dx.doi.org/10.1152/ajpregu.1991.261.3.r719.
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In mammals, the length of the loops of Henle increases with increasing body size without a concomitant rise in urinary concentrating ability. Because mass-specific metabolic rate falls with increasing body mass, this study sought to determine the extent to which this decline in metabolic rate could explain the low urinary concentrating ability of large mammals with long loops of Henle. Mitochondrial ultrastructural parameters were measured in the medullary thick ascending limbs (mTALs) of a series of nine mammalian genera ranging in body mass from 0.011 kg (bats) to approximately 400 kg (horses). The volume of mitochondria as a percent of mTAL cellular volume declined with increasing body mass (Mb-0.056). Inner mitochondrial membrane area per volume of mitochondrion also declined with increasing body mass (Mb-0.034), as did basolateral membrane area per unit mTAL cellular volume (Mb-0.075). Thus, not only do mitochondria occupy more volume of mTAL cells of smaller mammals, but those mitochondria are also more densely packed with cristae. Inner mitochondrial membrane area per unit volume of mTAL cell cytoplasm scaled as Mb-0.092. The decline in inner mitochondrial membrane area and basolateral membrane area per volume of mTAL cell may explain at least in part the relationship between body mass and renal concentrating ability in mammals of different sizes.
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Geiser, F., G. Körtner, and BS Law. "Daily Torpor In A Pregnant Common Blossom-Bat (Syconycteris Australis: Megachiroptera)." Australian Mammalogy 23, no. 1 (2001): 53. http://dx.doi.org/10.1071/am01053.
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TORPOR and reproduction in mammals are widely viewed as mutually exclusive processes. For most mammals, different energetic and hormonal demands appear to require a temporal sequence of torpor and reproduction within the yearly schedule. Torpor is characterised by a pronounced fall in body temperature and metabolic rate, which results in an overall reduction of energy expenditure (Geiser and Ruf 1995) and in most mammals occurs during the non-reproductive season (Goldman et al. 1986; Barnes 1996). Reproduction, on the other hand, requires an increase of energy expenditure for acquiring, processing and transfer of nutrients to the growing offspring (Hoffman 1964; Goldman et al. 1986; Thompson and Nicoll 1986; Kenagy et al. 1989; Barnes 1996).
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Deem, Jennifer D., Kenjiro Muta, Kayoko Ogimoto, et al. "Leptin regulation of core body temperature involves mechanisms independent of the thyroid axis." American Journal of Physiology-Endocrinology and Metabolism 315, no. 4 (2018): E552—E564. http://dx.doi.org/10.1152/ajpendo.00462.2017.
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The ability to maintain core temperature within a narrow range despite rapid and dramatic changes in environmental temperature is essential for the survival of free-living mammals, and growing evidence implicates an important role for the hormone leptin. Given that thyroid hormone plays a major role in thermogenesis and that circulating thyroid hormone levels are reduced in leptin-deficient states (an effect partially restored by leptin replacement), we sought to determine the extent to which leptin’s role in thermogenesis is mediated by raising thyroid hormone levels. To this end, we 1) quantified the effect of physiological leptin replacement on circulating levels of thyroid hormone in leptin-deficient ob/ob mice, and 2) determined if the effect of leptin to prevent the fall in core temperature in these animals during cold exposure is mimicked by administration of a physiological replacement dose of triiodothyronine (T3). We report that, as with leptin, normalization of circulating T3 levels is sufficient both to increase energy expenditure, respiratory quotient, and ambulatory activity and to reduce torpor in ob/ob mice. Yet, unlike leptin, infusing T3 at a dose that normalizes plasma T3 levels fails to prevent the fall of core temperature during mild cold exposure. Because thermal conductance (e.g., heat loss to the environment) was reduced by administration of leptin but not T3, leptin regulation of heat dissipation is implicated as playing a uniquely important role in thermoregulation. Together, these findings identify a key role in thermoregulation for leptin-mediated suppression of thermal conduction via a mechanism that is independent of the thyroid axis.
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More, Heather L., and J. Maxwell Donelan. "Scaling of sensorimotor delays in terrestrial mammals." Proceedings of the Royal Society B: Biological Sciences 285, no. 1885 (2018): 20180613. http://dx.doi.org/10.1098/rspb.2018.0613.
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Whether an animal is trying to escape from a predator, avoid a fall or perform a more mundane task, the effectiveness of its sensory feedback is constrained by sensorimotor delays. Here, we combine electrophysiological experiments, systematic reviews of the literature and biophysical models to determine how delays associated with the fastest locomotor reflex scale with size in terrestrial mammals. Nerve conduction delay is one contributor, and increases strongly with animal size. Sensing, synaptic and neuromuscular junction delays also contribute, and we approximate each as a constant value independent of animal size. Muscle's electromechanical and force generation delays increase more moderately with animal size than nerve conduction delay, but their total contribution exceeds that of the four neural delays. The sum of these six component delays, termed total delay, increases with animal size in proportion to M 0.21 —large mammals experience total delays 17 times longer than small mammals. The slower movement times of large animals mostly offset their long delays resulting in a more modest, but perhaps still significant, doubling of their total delay relative to movement duration when compared with their smaller counterparts. Irrespective of size, sensorimotor delay is likely a challenge for all mammals, particularly during fast running.
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Guiden, Peter W., and John L. Orrock. "Invasive shrubs modify rodent activity timing, revealing a consistent behavioral rule governing diel activity." Behavioral Ecology 30, no. 4 (2019): 1069–75. http://dx.doi.org/10.1093/beheco/arz050.
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Abstract Animals adjust the timing of their activity to maximize benefits, such as access to resources, and minimize costs, such as exposure to predators. Despite many examples of invasive plants changing animal behavior, the potential for invasive plants to alter the timing of animal activity remains unexplored. In eastern North America, invasive shrubs might have particularly strong effects on animal activity timing during spring and fall, when many invasive shrubs retain their leaves long after native species’ leaves senesce. We experimentally removed an invasive shrub (buckthorn, Rhamnus cathartica) and monitored the activity timing of a ubiquitous small-mammal species (white-footed mouse, Peromyscus leucopus) in spring, summer, and fall. We captured nearly 3 times as many P. leucopus in plots invaded by R. cathartica compared with plots with R. cathartica removed, and P. leucopus were captured 2 h earlier in invaded plots. Regardless of invasion treatment, P. leucopus appear to follow a common rule to set activity timing: P. leucopus were only active below a threshold of ground-level moonlight illuminance (0.038 lux). Diel and monthly lunar cycles play an important role in regulating small-mammal activity, but our data suggest that decreased light penetration dampens the influence of moonlight illuminance in habitats invaded by R. cathartica, allowing P. leucopus to remain active throughout the night. By changing the temporal niche of ubiquitous native animals, invasive shrubs may have unappreciated effects on many ecological interactions, including processes that alter community diversity and affect human health.
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Rocha, Carlos Frederico Duarte, Helena Godoy Bergallo, Carla Fabiane Vera y Conde, Emerson Brum Bittencourt, and Hilda de Carvalho Santos. "Richness, abundance, and mass in snake assemblages from two Atlantic Rainforest sites (Ilha do Cardoso, São Paulo) with differences in environmental productivity." Biota Neotropica 8, no. 3 (2008): 117–22. http://dx.doi.org/10.1590/s1676-06032008000300011.
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We analyzed richness, composition and mass of snakes in two sites in the Atlantic forest of Ilha do Cardoso (25º 03' S and 47º 53' W), an island (22,500 ha), Cananéia municipality, São Paulo State, Brazil. A monthly index of arthropod availability (in mm³) was estimated in each site through capture rates in pit-fall traps. Fallen fruits were collected along trails in the study sites (mass of fruit gave an index of fruit availability) and small mammals were sampled in grids with 120 traps which covered the lowland (5.2 ha) and in the slope forests (3.6ha). The abundance and mass of small mammals were standardized for the size of each sampled area (in g.ha-1). To sample snakes we established 20 pit-fall traps in each area and performed monthly transects in four consecutive days (totaling 1000 m long) along trails in the study sites. Snakes found were measured, weighted marked and released. Abundance and total mass of snakes were standardized by the size of each area. The areas differed consistently in in the productivity of arthropods, fruits and small mammals, and also in richness, composition and total mass of snakes. We found 36 individuals (total mass = 9884 g) of 12 snake species belonging to three Families (Colubridae, Elapidae and Viperidae) in the lowland forest, whereas in the slope forest we sampled only 9 individuals of 2 species (total mass = 1820 g). Our results suggest that the area of lowland forest, showing higher productivity of arthropods, fruits and small mammals, maintains a snake community with a higher richness, diversity and biomass than its slope forest counterpart.
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Murariu, Dumitru T. "Extinction and Radiation: How the Fall of Dinosaurs Led to the Rise of Mammals." Journal of Mammalogy 96, no. 5 (2015): 1106–7. http://dx.doi.org/10.1093/jmammal/gyv087.
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Bremer, K., K. M. Kocha, T. Snider, and C. D. Moyes. "Energy metabolism and cytochrome oxidase activity: linking metabolism to gene expression." Canadian Journal of Zoology 92, no. 7 (2014): 557–68. http://dx.doi.org/10.1139/cjz-2013-0267.
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Modification of mitochondrial content demands the synthesis of hundreds of proteins encoded by nuclear and mitochondrial genomes. The responsibility for coordination of this process falls to nuclear-encoded master regulators of transcription. DNA-binding proteins and coactivators integrate information from energy-sensing pathways and hormones to alter mitochondrial gene expression. In mammals, the signaling cascade for mitochondrial biogenesis can be described as follows: hormonal signals and energetic information are sensed by protein-modifying enzymes that in turn regulate the post-translational modification of transcription factors. Once activated, transcription-factor complexes form on promoter elements of many of the nuclear-encoded mitochondrial genes, recruiting proteins that remodel chromatin and initiate transcription. One master regulator in mammals, PGC-1α, is well studied because of its role in determining the metabolic phenotype of muscles, but also due to its importance in mitochondria-related metabolic diseases. However, relatively little is known about the role of this pathway in other vertebrates. These uncertainties raise broader questions about the evolutionary origins of the pathway and its role in generating the diversity in muscle metabolic phenotypes seen in nature.
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Fancy, S. G., L. F. Pank, K. R. Whitten, and W. L. Regelin. "Seasonal movements of caribou in arctic Alaska as determined by satellite." Canadian Journal of Zoology 67, no. 3 (1989): 644–50. http://dx.doi.org/10.1139/z89-093.
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Between 1985 and 1987, 49 283 locations and 79 101 sets of activity data were obtained for 34 adult female caribou (Rangifer tarandus granti) of the Porcupine and Central Arctic herds using satellite telemetry. Daily movement rates of female caribou from the two herds, which differ greatly in size and separation of seasonal ranges, were similar except during the spring and fall migration periods. Movement rates in July exceeded those during migration in both herds. The minimum annual distances travelled by caribou cows, ranging to 5055 km, were the longest movements documented for any terrestrial mammal.
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Rouse, Greg W., Shana K. Goffredi, Shannon B. Johnson, and Robert C. Vrijenhoek. "Not whale-fall specialists, Osedax worms also consume fishbones." Biology Letters 7, no. 5 (2011): 736–39. http://dx.doi.org/10.1098/rsbl.2011.0202.
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Marine annelid worms of the genus Osedax exploit sunken vertebrate bones for food. To date, the named species occur on whale or other mammalian bones, and it is argued that Osedax is a whale-fall specialist. To assess whether extant Osedax species could obtain nutrition from non-mammalian resources, we deployed teleost bones and calcified shark cartilage at approximately 1000 m depth for five months. Although the evidence from shark cartilage was inconclusive, the teleost bones hosted three species of Osedax , each of which also lives off whalebones. This suggests that rather than being a whale-fall specialist, Osedax has exploited and continues to exploit a variety of food sources. The ability of Osedax to colonize and to grow on fishbone lends credibility to a hypothesis that it might have split from its siboglinid relatives to assume the bone-eating lifestyle during the Cretaceous, well before the origin of marine mammals.
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Beltran, Roxanne S., Jennifer M. Burns, and Greg A. Breed. "Convergence of biannual moulting strategies across birds and mammals." Proceedings of the Royal Society B: Biological Sciences 285, no. 1878 (2018): 20180318. http://dx.doi.org/10.1098/rspb.2018.0318.
Full textAbstract:
Birds and mammals have developed numerous strategies for replacing worn feathers and hair. Moulting usually occurs on an annual basis; however, moults that take place twice per year (biannual moults) also occur. Here, we review the forces driving the evolution of various moult strategies, focusing on the special case of the complete biannual moult as a convergence of selection pressures across birds and mammals. Current evidence suggests that harsh environmental conditions or seasonality (e.g. larger variation in temperatures) drive evolution of a biannual moult. In turn, the biannual moult can respond to secondary selection that results in phenotypic alteration such as colour changes for mate choice dynamics (sexual selection) or camouflage requirements (natural selection). We discuss the contributions of natural and sexual selection to the evolution of biannual moulting strategies in the contexts of energetics, niche selection, functionality and physiological mechanisms. Finally, we suggest that moult strategies are directly related to species niche because environmental attributes drive the utility (e.g. thermoregulation, camouflage, social dynamics) of the hair or feathers. Functional efficiency of moult may be undermined if the pace of evolution fails to match that of the changing climate. Thus, future research should seek to understand the plasticity of moult duration and phenology, especially in the context of annual cycles.
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Krebs, Charles J. "Population dynamics of large and small mammals: Graeme Caughley's grand vision." Wildlife Research 36, no. 1 (2009): 1. http://dx.doi.org/10.1071/wr08004.
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Ecologists that study the population dynamics of large and small herbivorous mammals operate in two worlds that overlap only partly, and in this paper I address whether the conjecture that these worlds represent two distinct and valid paradigms is currently justified. I argue that large mammals fall into three groups depending on whether they have effective predators or not, and whether they are harvested by humans. Because of human persecution of large predators, more and more large herbivorous mammals are effectively predator-free and are controlled bottom-up by food. But in less disturbed systems, large herbivorous mammals should be controlled top-down by effective predators, and this can lead to a trophic cascade. Small herbivorous mammals have been suggested to be controlled top-down by predators but some experimental evidence has challenged this idea and replaced it with the notion that predation is one of several factors that may affect rates of population increase. Intrinsic control (territoriality, infanticide, social inhibition of breeding) appears to be common in small herbivorous mammals with altricial young but is absent in species with precocial young, in ecosystems with strong stochastic weather variation (deserts) and in areas of human-induced habitat fragmentation in agricultural monocultures. The extrinsic control of large herbivores with precocial young validates part of Graeme Caughley’s Grand Vision, but the relative role of intrinsic and extrinsic mechanisms for small herbivores with altricial young is still controversial. An improved knowledge of population control mechanisms for large and small herbivores is essential for natural resource management.
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MORRIS, PAT. "Extinction and radiation: how the fall of the dinosaurs led to the rise of mammals." Zoological Journal of the Linnean Society 164, no. 3 (2012): 715–16. http://dx.doi.org/10.1111/j.1096-3642.2012.00807.x.
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