Academic literature on the topic 'Giraffe (Giraffa camelopardalis)'

AbstractAcross Africa the majority of giraffe species and subspecies are in decline, whereas the South African giraffe Giraffa camelopardalis giraffa remains numerous and widespread throughout southern Africa. By 2013 the number of giraffes in South Africa's Kruger National Park had increased by c. 150% compared to 1979 estimates. An even greater increase occurred on many of the estimated 12,000 privately owned game ranches, indicating that private ownership can help to conserve this subspecies. The estimated total population size in South Africa is 21,053–26,919. The challenge now is to implement monitoring and surveillance of G. camelopardalis giraffa as a conservation priority and to introduce sustainable practices among private owners to increase numbers and genetic variation within in-country subspecies.

Abstract Giraffe social behaviour and relationships are currently in the period of scientific renaissance, changing the former ideas of nonexisting social bonds into understanding of complex social structures of giraffe herds. Different giraffe subspecies have been studied in the wild and only one was subject of detailed study in captivity. Our study focused on the neglected Cape giraffe (Giraffa camelopardalis giraffa). We investigated the social preferences of 28 introduced giraffes in semi-captivity in Bandia reserve, Senegal. Our aim was to assess the group size of Cape giraffes outside their native range and describe their social relationships. Mean group size in Bandia was 7.22 ± 4.06 (range 2-17). The dyads were classified according to strength of relationship (weak, medium, strong) using the association index. We reported weak and medium relationships in all types of dyads except female-juvenile. The strongest bond was found in mother-calf dyads. Three of 21 possible female dyads also demonstrated strong relationships. Those three dyads included six of seven adult females, which we labelled as friends. Females associated more frequently with calves of their friends then with calves of non-friend females. The strength of the relationship between calves depended on the strength of relationship between their mothers. We concluded that Cape giraffes in new environment have shown similar group size and nonrandom preference for conspecifics as shown in wild and captive studies. The research was supported by CIGA 20135010, CIGA 2134217, IGA FTZ 20135123, ESF/MŠMT CZ.1.07/2.3.00/30.0040.

AbstractThornicroft's giraffe Giraffa camelopardalis thornicrofti is limited in distribution to a single population resident in the Luangwa Valley, Zambia. During 1973−2003 regular counts were recorded along the Luangwa River in the core section of the subspecies’ range. In 2013 we conducted a count in the same region for comparison with the earlier survey results. During the 30-year period 1973−2003 the giraffe index (no. of individuals per km surveyed) was relatively stable, with an increase in 1994 and 1995 coinciding with an influx of giraffes to the west bank following an exceptionally reduced flow of the Luangwa River. The mean giraffe index during this period was 0.51 km−1, whereas the 2013 count yielded an index of 0.44 km−1. Given the limited range of the Thornicroft's giraffe, we estimate that the population comprises c. 500–600 individuals.

The social organization of giraffes ( Giraffa camelopardalis ) imposes a high-cost reproductive strategy on bulls, which adopt a ‘roving male’ tactic. Our observations on wild giraffes confirm that bulls indeed have unsynchronized rut-like periods, not unlike another tropical megaherbivore, the elephant, but on a much shorter timescale. We found profound changes in male sexual and social activities at the scale of about two weeks. This so far undescribed rutting behaviour is closely correlated with changes in androgen concentrations and appears to be driven by them. The short time scale of the changes in sexual and social activity may explain why dominance and reproductive status in male giraffe in the field seem to be unstable.

A 10-y-old giraffe ( Giraffa camelopardalis reticulata) bull developed colic after a 3-mo history of reduced feed consumption. Physical examination and management were performed with 2 standing sedations. The giraffe developed metabolic alkalosis and progressive pre-renal azotemia followed by compensatory respiratory acidosis and paradoxical aciduria. A metallic “ping” sound was auscultated on the left side near ribs 10–12. The giraffe was euthanized given the grave prognosis, and postmortem examination confirmed left displacement of the abomasum (LDA) with fluid sequestration (150–190 L [40–50 gal]) within the rumen. Dental disease was evident at postmortem examination and perimortem skull computed tomography. To ensure cases of LDA are not overlooked, the position of the abomasum must be noted during postmortem examination prior to removal of the gastrointestinal tract. The risk factors for the development of LDA in giraffes are not known, and associations such as those of dairy cattle (hypocalcemia, high-concentrate low-fiber diet, and indoor housing) remain to be elucidated.

Giraffe (Giraffa camelopardalis) is one of the flagship herbivore species in the savanna ecosystem and is of high conservation value. Management of the species under diversified ecosystems, particularly, their introduction in new ecosystems is of great concern, given that limited information is available of how the species acclimatizes to new ecosystems and which forage species it selects. The objectives of the present study were to (i) identify woody plant species selected by the recently introduced giraffes and (ii) determine whether there were differences in woody plant diversity between the dry and wet seasons in Umfurudzi Park, northern Zimbabwe. Forage selection and woody composition data were collected from a herd of giraffe between May and December 2016, using the focal observation method in an enclosure within the study area. A total of 106 observation plots were established. Our results showed that 12 woody plant species comprising six families were selected from a total of 29 woody plant species recorded in the study area. Giraffe showed a higher preference of the selected species in the dry season than in the wet season. In contrast, no significant differences were recorded in terms of forage availability and woody vegetation diversity between seasons. In conclusion, our results suggest that plant phenology, particularly, presence of leaves on plants influences giraffe feed preferences. Establishing long-term monitoring plots to determine woody vegetation utilisation by giraffes is valuable as a way to monitoring habitat utilisation by the species.

Doctor of Philosophy
The population size and range of giraffe Giraffa camelopardalis have been greatly reduced in Africa in the past century, resulting in geographical isolation of local populations and some herds surviving at the edge of the species’ preferred range. Numerous factors have contributed to these declines, but historical analysis indicates that habitat loss and fragmentation, human encroachment, disease and poaching are the main threatening processes. These processes can be expected to continue to impact on giraffe populations, particularly as human populations grow and needs for land and resources increase. This study used field data and laboratory analyses to investigate the taxonomy, behaviour and ecology of desert-dwelling giraffe Giraffa camelopardalis angolensis in the northern Namib Desert. This population resides at the extreme of the giraffe’s range. My research also complements the community-based natural resource management (CBNRM) program of the Namibian government, and provides baseline data on the current population status and structure of giraffe in the Kunene Region. The field data, genetic, habitat and forage samples used in this study were collected by myself and a number of research assistants over a period of two years (2001 to 2003), following preliminary research that I undertook between 1999 and 2001. Laboratory analysis of genetic samples was conducted by Dr R. Brenneman and his team at Henry Doorly Zoo, Omaha, NB., as well as by Mr D. Brown at UCLA, CA. Mr W. Gawa!nab and his team at the agricultural laboratory, Ministry of Agriculture, Water and Rural Affairs, Namibia, conducted chemical analyses on plant samples that form part of the giraffe’s diet. The genetic architecture of Namibian giraffe was investigated, including the samples from the desert-dwelling giraffe of the northern Namib Desert and giraffe from Etosha National Park. The results were compared with genetic profiles of giraffe subspecies throughout Africa, but in particular with G. c. giraffa which is the currently-accepted nomenclature of the Namibian giraffe. Results indicated that the Namibian giraffe has five unique haplotypes and is genetically distinct from G. c. giraffa or any other extant subspecies; it is considered here, tentatively, to represent G. c. angolensis. Furthermore, the Namibian Abstract iv giraffe has been separated from other populations for an extended period. Some gene flow has occurred between the desert-dwelling and Etosha NP giraffe population, and can be attributed to recent translocations between these regions. Within the study region, a sharing of haplotypes between three studied subpopulations indicated gene flow among giraffe throughout the northern Namib Desert, and this was confirmed by field-based monitoring. Taken together, these findings suggest that Namibian giraffe should be viewed as important for the conservation of overall genetic variation within Giraffa camelopardalis, although further investigation into the taxonomy of the Namibian form is warranted. Following these findings, I then investigated the behaviour and ecology of the desert-dwelling giraffe. As no previous study has been published on the ecology of G. c. angolensis, there is an information gap in our knowledge of this subspecies. One hundred and fifty six giraffe were identified individually using field-based identification methods and digital imagery. An assessment of the population structure and dynamics indicated marked variation in numbers, sex and age structure, herd structure and densities between three study areas. These variations possibly arose from differences in study area size, aridity, availability of forage and human impacts. I also investigated levels of associations between giraffe within the population using a simple ratio technique, and observed that increased association occurred in smaller populations; there appeared to be a matrilineal social structure. In one bull-biased population, a higher degree of association between bulls was observed compared to bulls in the other two populations. To gain further insight into the distribution and range of giraffe, I collected GPS locations from a combination of field-based monitoring and GPS satellite collars. The GPS satellite collars were the first trial of this technology on giraffe in Africa. Using Range Manager, a MapInfo animal location analysis extension program, I estimated 100% and 95% minimum convex polygon for daily, monthly and annual home range sizes of giraffe in the northern Namib Desert. Giraffe were observed to have large home ranges, with the largest individual range for a bull, Africa-wide, being recorded in this study. Large home ranges correlated with low population density, reduced diversity of forage and, in bulls, increased search areas for receptive cows. Giraffe movements occurred predominantly along riparian woodlands, although seasonal use of other habitats was recorded. Observations Abstract v Abstract vi and data from four GPS satellite-collared giraffe provided high-resolution data on daily movements, and indicated a pattern of highly biphasic movement behaviour that correlated with ambient temperatures. Diurnal activity budgets varied between the sexes, with cows spending more time feeding and resting, while bulls walked and ruminated more frequently. Juveniles rested more often than other giraffe. Seasonal variation in activity budgets was evident, perhaps reflecting use of an energy maximiser strategy for cows and an energy minimiser strategy for bulls. The establishment of artificial water points in the Hoanib River during the study period appeared to alter the seeming independence of giraffe on water in the northern Namib Desert, and also resulted in small-scale shifts in use of the riparian woodland by elephant. To investigate the diet of giraffe, I observed animals feeding in the field and also carried out laboratory analyses of the chemical content of preferred plant species. Seasonal changes in the abundance, moisture and protein content of available food plants correlated with shifts in the diet of giraffe. Giraffe impacted on their preferred forage source, Faidherbia albida, causing distinct structural changes in the individual plants and the F. albida population. This impact, combined with elephant damage and seasonal flood events, has resulted in a shift in the age structure and dynamics of the F. albida population over the past two decades. Finally, I present a brief overview on the history of conservation and management in the Kunene Region. The established CBNRM program provides a baseline for future wildlife conservation and management, of which the desert-dwelling giraffe could be an integral component for non-consumptive tourism. Long-term research on the population’s status, range, behaviour, social structure, habitat requirements, and ecology would help to provide a better understanding of the giraffe’s adaptation to the arid environment, while focussed legislation would enable increased control of communal lands and continue to benefit community-based conservancies.

Giraffes (Giraffa camelopardalis) have evolved into a unique and extreme shape. The principle determinant of its shape is the skeleton and the overarching theme of the study was to describe how this shape is achieved throughout ontogeny. Accordingly, the study had three main objectives: 1) To describe the growth of the giraffe postcranial skeleton allometrically, 2) To interpret the allometric patterns described in an evolutionary and functional sense and 3) To reconstruct the size and shape of the extinct Giraffa sivalensis using, if feasible, allometric equations obtained in this study. Secondary objectives were to a) establish if sexual dimorphism was evident in G. camelopardalis and b) determine if growth patterns in the foetus differed from those in postnatal G. camelopardalis. Data were collected from giraffes culled as part of conservancy management in Zimbabwe. The sample included 59 animals from which vertebral dimensions were taken in 48 animals and long bone dimensions in 47 animals. Body masses ranged from 21 kg to 77 kg in foetuses and 147 kg to 1412 kg postnatally, representing 29 males and 30 females. In addition to body mass, external body dimensions were recorded from each animal. Each vertebra and unilateral long bone was dissected from the carcasses and cleaned, after which dimensions were measured with a vernier calliper, measuring board or measuring tape. Vertebral dimensions measured included body (centrum) length, height and width as well as vertebral spinous process length. Long bone dimensions included length, two midshaft diameters and circumference. Allometric equations (y=bxk) were constructed from the data, with special interest in the scaling exponent (k) to illustrate regions of positively allometric, isometric or negatively allometric growth. In the first series of analyses the growth patterns of the components of the postcranial axial skeleton were analysed. The adaptations in vertebral growth to create and maintain extraordinary shape were identified as disproportionate elongation of the cervical vertebrae after birth, increasing cross sectional diameters of the cervical vertebrae from cranial to caudal and positively allometric spinal process growth. The theory of sexual selection as a driver for neck elongation in giraffes was brought into question by showing that male and female vertebral elongation rates are similar relative to increases in body mass. The second series of analyses described the growth pattern of the long bones of the appendicular skeleton. The allometric exponents seemed unremarkable compared to the few species described previously, and it was shown that the giraffe appendicular skeleton does not elongate in the dramatic way the neck does. Limbs at birth, after lengthening with positive allometry in utero, are already elongated and slender in shape and a further increase in the gracility of the bones is either not possible or not desirable. This result implies that it is neck elongation rather than leg elongation that is the dominant factor in the evolution of the giraffe shape. Nevertheless, the front limb bones and especially the humerus may show responsiveness to increasing high loads and/ or bending moments, which may be caused by the neck mass which increases with positive allometry, or with behaviours such as splaying the forelegs during drinking. In the third component of the study ontogenetic allometric equations in extant giraffes were applied to the remains of an extinct giraffid, G. sivalensis. The procedure was unusual as it employed ontogenetic regressions instead of the more commonly used interspecific regressions. The appropriateness of each equation to estimate body mass was evaluated by calculating the prediction error incurred in both extant giraffes and okapis (Okapia johnstoni). It was concluded that, due to body shape, ontogenetic equations were adequate and perhaps preferable to interspecific equations to estimate proportions in Giraffa species. This analysis showed that G sivalensis was smaller than extant giraffes and weighed around 400 kg (range 228 kg 575 kg), with a neck length of about 147 cm and a height of 390 cm. There may be evidence of sexual dimorphism in this species, with males being about twice the body weight of females. However, if sexual dimorphism was not present and all the bones were correctly attributed to this species, then G. sivalensis had a slender neck with a relatively stocky body. In conclusion, this study established ontogenetic regression equations for the skeleton of an animal of which the body shape seems to be at the extreme limits of mammalian possibility. The value of the current study lies especially in its sample size and quality, which included an unprecedented number of giraffe body masses, vertebral and long bone dimensions. This dataset had applications in the giraffe s evolutionary biology, palaeontology and even ecology. Future studies still need to compare the findings from giraffe growth with similar data from other taxa, especially those with long legs and necks. Specifically, it would interesting to determine if positively allometric neck growth combined with isometric leg growth is found in other mammalian species. In addition, the strength of giraffe long bones and vertebrae needs to be investigated with more accuracy using parameters like second moment of area. Lastly, further palaeontological studies on other giraffid sizes are necessary to validate the current and future interpretations of fossil giraffid findings.
Thesis (PhD)--University of Pretoria, 2015.
tm2016
Production Animal Studies
PhD

The giraffe at Nyaru were found to be browsers who made little use of graze during the study period. They utilized a diversity of 20 browse species. Two species, Acacia karroo and Acacia cyclops, formed the bulk of the giraffe diet throughout the year. A definite seasonal dietary shift was evident. A. karroo was favoured in summer and autumn and formed the main food species in spring, summer and autumn. A. cyclops was favoured throughout the study, but its contribution to the diet increased during winter when less A. karroo was consumed. This seasonal shift is related to the deciduous nature of Acacia karroo. Although a seasonal shift in species contribution to giraffe diet has been observed in many other giraffe feeding studies, no studies on giraffe feeding have been done in the Mosaic Thicket of the southern Cape. The ecological browsing capacity for giraffe in thicket was estimated to be between 0.020 BU/ha and 0.095 BU/ha. The browsing capacity for giraffe at Nyaru, based on the available phytomass 2–5 m above the ground, was estimated using those species that formed the bulk of the giraffe diet, and amounted to 0.063 BU/ha. A maximum of three giraffe could thus be stocked on the 157 ha of suitable giraffe habitat on Nyaru. This stocking rate recommendation lies within the range commonly recommended by local consultants for giraffe introductions into the southern Cape. Their recommendations are, however, not based on quantitative assessments such as performed in this study. The recommendation of this study should not be applied as a fixed ecological capacity for giraffe in thicket, but should be seen as a starting point in the adaptive management cycle. Ongoing monitoring of parameters, such as herbaceous composition and phytomass; as well as the condition of key browse species, is strongly advocated. A. karroo was browsed significantly more and carried significantly fewer pods per tree at a heavily used site compared to a lightly used site. Heavy browsing thus appears to affect the reproductive success of A. karroo significantly. Fewer pods are likely to lead to lower regeneration and thus reduced density of A. karroo. Whether A. karroo will maintain its dominance within the thicket vii community in the long run will be related to how individual plants survive and reproduce and if some can escape from herbivory. Fewer G. occidentalis were clumped with other species at the heavily used site compared to the lightly used site. This could possibly be attributed to the fact that intense browsing pressure at the heavily used site caused protective clumps to be eaten away, thus exposing G. occidentalis to higher ungulate browsing. Previous studies have found that nurse shrubs protect G. occidentalis against ungulate browsing. G. occidentalis was browsed significantly more at the heavily used site compared to the lightly used site. There was a general trend of fewer fruits at the heavily used site compared to the lightly used site, while fruits were absent on G. occidentalis growing alone at the heavily used site. This suggests a negative effect of heavy browsing on plant reproductive success and emphasizes the importance of nurse plants for the successful recruitment and hence long term prevalence of G. occidentalis in Mosaic Thicket.

Apart from its slender appearance, four main factors lead to questions regarding the bone density, mineral content and morphology of the giraffe skeleton: X A rapid vertical growth rate ¡V especially in the neck and metapodials X Biomechanical considerations pertaining to the tall and slender shape of the skeleton X A proportionally larger skeleton in relation to body mass X A seemingly abnormal mineral balance in their diet with possible signs of mineral deficiency (i.e. osteophagia) In this study the skeleton of the giraffe was compared with that of the African buffalo with regards to bone density, skeletal calcium (Ca) and phosphorus (P) content and certain femoral and metacarpal morphological characteristics. The aim was to establish if, compared to buffalo, the features of the giraffe skeleton differed in any unique way. Fourteen similar bones or parts of bones were collected from carcasses of six adult giraffe bulls and nine adult buffalo bulls. These bones were cleaned, weighed and their volume determined through water displacement, from which their density could be calculated. Hereafter, Ca and P content were analysed in 10 bones from each carcass. Morphological characteristics of cross-sections from femoral and metacarpal shafts were also measured. No significant differences between the density or mineral content of bones in the two species could be found. In both species 19,5% Ca and 9,5% P were measured in defatted bone. Although similar in mineral concentration, the giraffe skeleton contains three times more absolute Ca and P, which translates into a 1,5-2-fold higher dietary requirement for these minerals compared to buffaloes. A gradation in the volume and weight of cervical vertebrae was also seen in giraffes. This could hold biomechanical advantage for the carriage and manoeuvrability of the long neck. Bone wall thickness of the giraffe femur and metacarpus is increased compared to buffaloes. This could hold biomechanical advantage for the slender legs that are subjected to increased vertical forces. Adequate Ca seems to be acquired through very specific browse selection, which seems to be of evolutionary origin, while the acquisition of adequate P seems to be critical and a possible cause for osteophagia. This study is the first of its kind in these species and therefore also provide valuable baseline data for future work in this field.
Dissertation (MSc (Veterinary Science))--University of Pretoria, 2004.
Production Animal Studies
unrestricted

This thesis examines the subspecific taxonomic status of the giraffe and considers the role of formal taxonomy in the formulation of conservation policy. Where species show consistent. geographically structured phenotypic variation such geographic patterns may indicate selective forces (or other population-level effects) acting . upon local populations. These consistent geographic patterns may be recognised formally as subspecies and may be of interest in single or multi-species biodiversity or biogeography studies for delimiting areas of conservation priority. Subspecies may also be used in the formulation of management policies and legislation. Subspecies are, by definition, allopatric. This thesis explicitly uses methodology of systematic biology and phylogenetic reconstruction to investigate patterns of variation between geographic groups. The taxonomic status of the giraffe is apposite for review. The species provides three independent data sets that may be analysed quantitatively for geographic structure; pelage patterns, morphology and genetics. Museum specimens. grouped according to geographic origin, were favoured for study as more than one type of data was often available for an individual. Population aggregation analysis of forty pelage pattern characters maintained six separate subspecies, while agglomerating some neighbouring populations into a subspecies. A 'traditional' morphometric approach, using multivariate statistical analysis of adult skull measurements, was complemented by a geometric morphometric approach; landmarkrestricted eigenshape analysis. Four morphologically distinct groups were recognised by both morphological analyses. Phylogenetic analysis of mitochondrial DNA control region sequences indicates five major cIades. Nested cIade analysis identifies population fragmentation, range expansion and genetic isolation by distance as contributing to the genetic structure of the giraffe. The results of the analyses show remarkable congruence. These results are discussed in terms of the formulation of conservation policy and the differing requirements of'blological and legal classification systems. The value of a formal taxonomic framework to the recognition, and subsequent conservation, of biodiversity is emphasised.

Da die afrikanischen Spitzmaulnashörner in ihrer Heimat vom Aussterben bedroht sind, besitzt ihre Nachzucht in Zoologischen Gärten große Bedeutung. Zwar sind die Bestände der Giraffen in der Wildnis noch nicht besonders gefährdet, die Verlustrate dieser empfindlichen Tierart in menschlicher Obhut ist jedoch zu hoch. Die Gestagen-konzentrationen im Kot wurden bestimmt, um detailliertere Kenntnisse der Fortpflan-zungsphysiologie dieser beiden Spezies, die für eine erfolgreiche Reproduktion notwendig sind, zu erlangen. Die nichtinvasive Methode erwies sich als geeignet zur Überwachung der Fortpflanzung sowohl bei den Giraffen als auch den Spitzmaulnas-hörnern. Die Gestagenbestimmung im Kot erfolgte in 3 Schritten: Einwiegen des Kotes, Extraktion der Gestagene mit Hilfe von Methanol und ihre Bestimmung mittels Radioimmunoassay. Im methodischen Teil der Arbeit ergaben sich innerhalb einer Tierart (Giraffen, Spitzmaulnashorn und zusätzlich Damagazellen) nur geringfügige Schwankungen der Trockenmasse des Kotes von maximal 5 %, so dass sich auch bei unterschiedlichem Wassergehalt des Kotes ohne vorherige Trocknung der Proben gut vergleichbare Gestagenwerte in verschiedenen Kotproben der gleichen Tierart ermitteln lassen. Nach 24- bzw. 48-stündiger Lagerung bei Raumtemperatur waren im Kot von Giraffen und Nashörnern die Gestagenwerte im Vergleich zum sofortigen Einfrieren der Proben signifikant erhöht. Bei Nashörnern und Gazellen wurden nach längerer Lagerzeit (1 und 3 Monate) bei – 20 °C keine signifikanten Veränderungen der niedrigen Gestagen-konzentrationen im Kot festgestellt. Im Gegensatz dazu zeigte sich bei Kotproben von Giraffen mit hohen Ausgangskonzentrationen eine signifikante Erniedrigung (durchschnittlich 45 %). Im Vergleich zu einmaligem führte mehrmaliges Auftauen der Proben zum signifikanten Absinken der Gestagenkonzentrationen im Kot von Spitzmaulnashörnern und Gazellen. Im Ergebnis dieser Voruntersuchungen wurde für das weitere Vorgehen eine standardisierte Behandlung der Kotproben bis zur Bestimmung ihrer Gestagenkonzentrationen eingehalten. Bei 13 Giraffen und 8 östlichen Spitzmaulnashörnern aus 7 deutschen Zoos (insgesamt 2618 Kotproben) erfolgte zwischen 1997 und 2002 eine Zyklus- und/ oder Graviditäts-diagnostik mittels Gestagenbestimmungen im Kot. Dabei zeigten die Konzentrationen an Progesteronmetaboliten im Kot von 6 adulten, ingraviden Giraffen zyklische Schwankungen mit einer Zykluslänge von ca. 14 Tagen. Die Follikelphase dauerte im Mittel 6,9 Tage mit Gestagengehalten von durchschnittlich 259 ± 49 ng/g Kot und die Lutealphase hatte eine Länge von im Mittel 7,6 Tagen bei Konzentrationen an Progesteronmetaboliten von durchschnittlich 1163 ± 223 ng/g Kot. Brunstsymptome und/ oder Paarungen fielen immer mit dem Ende der Lutealphase zusammen. Am Beginn von 8 Graviditäten kam es bei den Giraffen zum Anstieg der Hormonkonzen-trationen auf Werte, die auch während der Lutealphase erreicht werden. Danach blieb die Gestagenausscheidung mit dem Kot zwischen der 58. und 1. Woche a. p. auf hohem Niveau. Eine Rückkehr auf Basalwerte, die während der Follikelphase auftreten, erfolgte erst 3 Tage p. p. Nach der Geburt konnten bei einigen Tieren postpartale Östren mit einer kurzfristigen Erhöhung der Hormonausscheidung im Kot festgestellt werden. Bei 7 adulten, ingraviden Spitzmaulnashörnern konnte mit der angewandten Methode kein Sexualzyklus ermittelt werden. Diese Tiere zeigten nur geringe Schwankungen der Gestagenausscheidung auf niedrigem Niveau (im Mittel 74 ± 18 ng/g Kot). Im Rahmen von 4 Graviditäten kam es bei den Spitzmaulnashörnern zunächst zu einer langsamen Erhöhung der Ausscheidung von Progesteronmetaboliten mit dem Kot, gefolgt von einem starken Anstieg ab der 56. Woche a. p. auf maximale Konzentrationen von ca. 674 ng/g Kot zwischen der 40. und 36. Woche a. p. Im weiteren Verlauf der Gravidität schwankten die Gestagengehalte zwischen 450-600 ng/g Kot. Eine Rückkehr auf das Niveau der Gestagenausscheidung von ingraviden Tieren war erst 3 Tage p. p. zu verzeichnen. Durch Festlegung eines Schwellenwertes von 200 ng/g Kot konnte eine Graviditätsdiagnose bei den Spitzmaulnashörnern ab etwa 52 Wochen vor der Geburt erfolgen. Eine Vorhersage des Geburtszeitpunktes war durch die Bestimmung der Gestagene im Kot weder bei Giraffen noch bei Spitzmaulnashörnern möglich
Since the African black rhinoceros is threatened to become extinct in its homeland, its offspring in zoological gardens possesses great importance. The existence of the giraffe is not yet particularly endangered in the wild, the loss of this sensible species in captivity is however very high. Gestagen concentrations in the faeces were determined in order to get more knowledge on the reproduction physiology of these two species, which is necessary for a successful reproduction. These non-invasive method was shown to be suitable for monitoring of the reproduction both in giraffes and black rhinoceroses. The gestagens in the faeces were analyzed in 3 steps: weighing of faeces specimens, gestagen extraction with methanol and their determination by means of radioimmunoassay. In the methodical part of the study the dry mass of the faeces showed only small variations up to 5 % within one species (Baringo giraffe, black rhinoceros and also dama gazelle). Thus, it was possible to estimate comparable gestagen levels from several faecal samples within one species without drying, in spite of their different amounts of water. After storage at room temperature for about 24 and/ or 48 hours gestagen concentrations in the faeces of giraffes and rhinoceroses were significantly increased in comparison to samples frozen immediately. After prolonged storage time (1 and 3 months) at – 20 °C no significant changes of low gestagen concentrations were stated in the faeces of rhinoceroses and gazelles. In opposite to this, in the faeces of giraffes with high initial gestagen concentrations a significant decrease (average 45 %) was evident. Repeated thawings of the samples led to a significant dropping of the gestagen levels in the faeces of rhinoceroses and gazelles compared to single thawing. As a result of these preceding investigations a standardized treatment of the faeces samples prior to determination of their gestagen concentrations was observed. Control of reproduction cycle and pregnancy respectively by means of faecal gestagen monitoring was carried out in a total of 2618 faecal samples of 13 giraffes and 8 eastern black rhinoceroses, collected in 7 German zoos from 1997 to 2002. Concentrations of progesterone metabolites in the faeces of 6 adult, nonpregnant giraffes showed cyclic fluctuations with a cycle length of approximately 14 days. The follicular phase took 6.9 days on an average with a mean gestagen concentration of 259 ± 49 ng/g faeces and the luteal phase had a length of 7.6 days on an average with a mean concentration of 1163 ± 223 ng/g faeces. Oestrus behaviour and/ or mating was observed always at the end of the luteal phase. A rise of hormone concentrations to a level, which is characteristic for the luteal phase, was evident at the beginning of 8 pregnancies in giraffes. Afterwards the excretion of faecal gestagens remained on a high level between week 58th and 1st a. p. Basal values, which are characteristic for the follicular phase, were detected 3 days p. p. After parturition some animals showed oestrus behaviour with a short increase of hormone excretion by the faeces. In 7 adult, nonpregnant black rhinoceroses no reproduction cycle could be ascertained by determination of gestagens in the faeces. Only small fluctuations of the gestagen excretion on a low level (on an average 74 ± 18 ng/g faeces) were evident in these animals. Within 4 pregnancies of black rhinoceroses a slow increase of the excretion of faecal progesterone metabolites could be detected, followed by a massive rise from week 56th a. p. to maximum concentrations of approximately 674 ng/g faeces between week 40th and 36th a. p. In the ongoing pregnancy the gestagen concentrations varied between 450-600 ng/g faeces. A return to the level of the gestagen excretion of nonpregnant animals was noticed 3 days p. p. Diagnosis of pregnancy of black rhinoceroses was possible approximately 52 weeks prior to parturition by defining a threshold value of 200 ng/g faeces. Prediction of the day of delivery by means of gestagen determination in the faeces was neither possible in giraffes nor in black rhinoceroses

The giraffe (Giraffa camelopardalis) occupies a variety of habitats across sub- Saharan Africa. It is characterised by a loose social organisation, and a dominancedriven polygynous mating system. This project sought to explain biogeographic and inter-sexual variation in pelage colouration in the context of natural and sexual selection. I also sought to test the hypothesis that in a semi-arid environment, limited resources (food and water) would predictably concentrate females, increasing the potential for dominant males to monopolise matings. I analysed photos from across Africa, and reveal that where yearly bright sunshine is greater, female giraffe in particular tend to be lighter, resulting in sexual dichromatism in high insolarity locations. I hypothesised that dark pelage colour is maintained in males through sexual selection for a costly status signal. Field work was carried out in Etosha NP, Namibia. Using photographic records, I identified 431 individual giraffe. I surveyed the study area regularly and collected data on group composition and behaviour upon locating giraffe. I carried out focal watches, and recorded all observations of agonistic and mating behaviour. Darker males tended to be older and more dominant than lighter males, associated less with females, but had greater success in courting females. Food and water affected female movements on both a spatial and temporal scale. At waterholes, encounter rates were increased and consequently mating and agonistic interactions more frequent. Paler males had a greater chance of interacting with females at waterholes because of higher intruder pressure, but when present, darker males always monopolised courtship opportunities. Mature males demonstrated a diversity of ranging strategies that affected association with females. These individual differences are assumed to relate to status and probably affect individual reproductive success. Evidence suggests male reproductive success is skewed towards mature dark males, but may also vary among dark males, with some potentially being excluded from mating.

An increasing number of species are declining in the wild. Giraffes have suffered an estimated 36-40% decline in the past ten years and are now listed as Vulnerable on the IUCN Red List of Threatened Species (Muller, 2016). Given this rate of decline, there is an urgent need for the development of conservation plans and practices for giraffes. However, giraffes have been understudied in relation to other large African mammals and even basic aspects of their behaviour and ecology are still unknown or misunderstood. Understanding a species’ social organisation and behaviour is critical to developing suitable conservation and management plans. In this thesis I provide a thorough investigation of giraffe social behaviour and the factors which influence association patterns and discuss how these may be related to fitness and impact upon the survival of the species. My results show that giraffes live in complex social systems which are composed of non-random associations, the patterns of which are influenced by age and sex of individual, behavioural state, reproductive state, and environmental factors such as disturbance and habitat structure. My results have contributed knowledge to understanding the complex social behaviour of giraffes and have demonstrated how generic conclusions about the behaviour of a species should not be drawn from studies of single populations. My study provides an important starting point from which to develop the comparative study of networks and determine the relative influence of environmental factors on network structure and provides comprehensive information that can be used for the management of giraffe populations in the wild.

Against the odds, over a period of 8 million years the genetic material in small gazelle-like Canthumerycids transformed by natural selection into modern long-legged, long-necked giraffes, Giraffa camelopardalis. How did that happen? The 8 million-year-long evolutionary gap between Canthumerycids and giraffes, during which the astonishing morphophysiological changes occurred, is filled by three ancestral species of Paleotragine giraffids—Giraffokeryx, Paleotragus, and Samotherium—that lived in southern central Europe, with each making small but significant evolutionary contributions. While all had elongated necks, their necks were never more than half the length of modern giraffes. All, though, had long legs. Long necks arose in Bohlinia, a unique species that evolved from the Paleotragine genetic pool. Bohlinia migrated to Asia and gave rise to Indian and Chinese giraffes, and also into North Africa. Relatively quickly the Indo-Asian giraffes became extinct. In Africa the giraffe lineage that produced modern giraffes began with the evolution of Giraffa jumae from Bohlinia about 6 million years ago. G. jumae was the origin of three ancestors of modern giraffes—G. stillei, G. gracilis, and G. pygmaea—that made their appearance in East Africa around 3 million years ago. Their appearance then was a consequence of major episodes of climate change. From their genetic pool, modern giraffes, G. camelopardalis, emerged 1 million years ago.

The modern scientific name of giraffes is Giraffa camelopardalis, given to the species by Mathurin Brisson and Carl Linnaeus in the eighteenth century. At that time a single species was thought to exist, but it soon became apparent that depending on where they lived in Africa giraffes had different skin markings and different “horns.” Thus the idea arose that there were more than one species, or if just one species then there were several different subspecies. Investigation of these two possibilities has depended partly on analysis of external characteristics, but mostly on the study of mitochondrial and nuclear DNA to establish if geographical distribution is associated with distinct genetic differences. These studies have indicated that there may be six separate species or four or three. However, as each of the variants can interbreed, genetic differences thus far have not resulted in reproductive isolation and the overall conclusion must be that there is one species with regional variants/subspecies that can be genetically distinct.