Academic literature on the topic 'Python brongersmai'

Short-tailed pythons (Python breitensteini, P. brongersmai and P. curtus) are exploited in large numbers for the international leather trade, but their ecology remains poorly known. We quantify sexual dimorphism and reproductive output in P. breitensteini from Kalimantan and P. brongersmai from sites in north and south Sumatra. Sexual dimorphism was more evident in P. breitensteini (males less heavy-bodied than females, and with longer heads relative to body length) than in either population of P. brongersmai. Although having a smaller average adult body size, P. breitensteini had a larger clutch size (mean of 17.2 eggs, versus 12.6 and 14.5 in the two brongersmai populations), and a higher reproductive frequency (92% of adult-size females reproductive, versus 38 and 50%). Female pythons from Kalimantan laid their eggs in September through November whereas female P. brongersmai from north Sumatra oviposited from March to May, in keeping with their geographic position either side of the equator. Paradoxically, however, P. brongersmai from south Sumatra apparently lay eggs at the same time as their northern conspecifics, despite their latitudinal position corresponding to our P. breitensteini study site. Reproductive traits within tropical snakes may be more diverse than is currently understood, even within clades of closely related taxa.

The evolutionary interplay between predator and prey has significantly shaped the development of snake venom, a critical adaptation for subduing prey. This arms race has spurred the diversification of the components of venom and the corresponding emergence of resistance mechanisms in the prey and predators of venomous snakes. Our study investigates the molecular basis of venom resistance in pythons, focusing on electrostatic charge repulsion as a defense against α-neurotoxins binding to the alpha-1 subunit of the postsynaptic nicotinic acetylcholine receptor. Through phylogenetic and bioactivity analyses of orthosteric site sequences from various python species, we explore the prevalence and evolution of amino acid substitutions that confer resistance by electrostatic repulsion, which initially evolved in response to predatory pressure by Naja (cobra) species (which occurs across Africa and Asia). The small African species Python regius retains the two resistance-conferring lysines (positions 189 and 191) of the ancestral Python genus, conferring resistance to sympatric Naja venoms. This differed from the giant African species Python sebae, which has secondarily lost one of these lysines, potentially due to its rapid growth out of the prey size range of sympatric Naja species. In contrast, the two Asian species Python brongersmai (small) and Python bivittatus (giant) share an identical orthosteric site, which exhibits the highest degree of resistance, attributed to three lysine residues in the orthosteric sites. One of these lysines (at orthosteric position 195) evolved in the last common ancestor of these two species, which may reflect an adaptive response to increased predation pressures from the sympatric α-neurotoxic snake-eating genus Ophiophagus (King Cobras) in Asia. All these terrestrial Python species, however, were less neurotoxin-susceptible than pythons in other genera which have evolved under different predatory pressure as: the Asian species Malayopython reticulatus which is arboreal as neonates and juveniles before rapidly reaching sizes as terrestrial adults too large for sympatric Ophiophagus species to consider as prey; and the terrestrial Australian species Aspidites melanocephalus which occupies a niche, devoid of selection pressure from α-neurotoxic predatory snakes. Our findings underline the importance of positive selection in the evolution of venom resistance and suggest a complex evolutionary history involving both conserved traits and secondary evolution. This study enhances our understanding of the molecular adaptations that enable pythons to survive in environments laden with venomous threats and offers insights into the ongoing co-evolution between venomous snakes and their prey.

Assessing the sustainability of the harvest of animals can be done by obtaining data from processing facilities and establishing that vital attributes of the harvested animals (e.g., size, age structure, sex ratio) do not change over time. This model works if the traders operate in a free market without any regulations on what can be harvested, processed or exported, and when harvest methods and harvest areas do not change between assessment periods. Several studies assessed the harvest effects on blood pythons (Python brongersmai) in North Sumatra, Indonesia seemingly under a free market scenario, with some concluding that trade was sustainable and the others hinting at an overharvest. Indonesia has established harvest and export quotas and, internationally, trade in blood pythons is regulated through CITES, and the blood python trade clearly does not operate in a free market. Data suggest that the three (or four) slaughterhouses included in these studies processed ~27,000 blood pythons a year against a quota of 18,000. There is a risk that data from traders alone purporting to show that harvest is sustainable will lead to an increase of quotas or an abandonment of quotas altogether. There is no conclusive data to support that the harvest of blood pythons in North Sumatra is sustainable but there is sufficient evidence to suggest that a substantial part of this trade is illegal. Likewise, at a global level there are clear indications of misdeclared, underreported and illegal trade involving 10,000 s of blood pythons. While important biological information can be obtained from harvested animals, to assess whether harvest is sustainable there is no substitute for monitoring wild populations. After decades of international trade in blood pythons from Indonesia, during which at least half a million blood pythons were exported, it is all the more urgent that systematic monitoring of wild populations commences.

Assessing the sustainability of the harvest of animals can be done by obtaining data from processing facilities and establishing that vital attributes of the harvested animals (e.g., size, age structure, sex ratio) do not change over time. This model works if the traders operate in a free market without any regulations on what can be harvested, processed or exported, and when harvest methods and harvest areas do not change between assessment periods. Several studies assessed the harvest effects on blood pythons (Python brongersmai) in North Sumatra, Indonesia seemingly under a free market scenario, with some concluding that trade was sustainable and the others hinting at an overharvest. Indonesia has established harvest and export quotas and, internationally, trade in blood pythons is regulated through CITES, and the blood python trade clearly does not operate in a free market. Data suggest that the three (or four) slaughterhouses included in these studies processed ~27,000 blood pythons a year against a quota of 18,000. There is a risk that data from traders alone purporting to show that harvest is sustainable will lead to an increase of quotas or an abandonment of quotas altogether. There is no conclusive data to support that the harvest of blood pythons in North Sumatra is sustainable but there is sufficient evidence to suggest that a substantial part of this trade is illegal. Likewise, at a global level there are clear indications of misdeclared, underreported and illegal trade involving 10,000 s of blood pythons. While important biological information can be obtained from harvested animals, to assess whether harvest is sustainable there is no substitute for monitoring wild populations. After decades of international trade in blood pythons from Indonesia, during which at least half a million blood pythons were exported, it is all the more urgent that systematic monitoring of wild populations commences.

Abstract ContextEach year, millions of reptile skins are commercially exported from Southeast Asia for exotic leathers. Quotas are commonly used to regulate this trade, but quotas are sometimes exceeded and do little to ensure harvest sustainability. AimsTo explore the relationship between the size of live pythons and their skins, and to assess whether skin measurements can be used to enforce the application of limits on the size of harvested snakes. MethodsWe measured the body size of three heavily harvested python species (Malayopython reticulatus, Python breitensteini and Python brongersmai) in Indonesia and Malaysia and examined the relationship with skin length, skin width, the size of the ventral scale and its adjacent dorsal scale. Key resultsMeasurements of 2261 pythons showed strong relationships between the size of live pythons and measurements made on their skins. Skins can be stretched 30% longer than the body length of snakes from which they came and inter-facility and country differences in stretching technique result in different relationships between the sizes of live snakes and the measurements made on their skins. Male and female Malayopython reticulatus differed in their skin dimensions relative to the size of the live snake, but these differences were minor. ConclusionsDespite variations in stretching techniques, in functional terms, this variation is minor (maximum 3.5% relative to each mean measurement) and does not limit application of skin sizes for regulating trade within an acceptable level of error. However, differences in the stretched length of Indonesian and Malaysian skins were much greater (5.9% of the mean length of skins), and, thus, each country should apply its own limits and predictive tools. ImplicationsThe strong relationship between the skin size and the size of the live snake offers great potential for regulating trade by using skin-size limits. Inspection of the size of skins can be used to enforce harvest-size limits and focus harvesting away from sexes and life stages most critical for population persistence. This management tool has numerous advantages over current regulatory practices (quotas) and should be considered for management of trade in Asian reptile skins.

Snake strikes are some of the most rapid accelerations in terrestrial vertebrates. Generating rapid body accelerations requires high ground reaction forces, but on flat surfaces snakes must rely on static friction to prevent slip. We hypothesize that snakes may be able to take advantage of structures in the environment to prevent their body from slipping, potentially allowing them to generate faster and more forceful strikes. To test this hypothesis, we captured high-speed video and forces from defensive strikes of juvenile blood pythons (Python brongersmai) on a platform that was either open on all sides or with two adjacent walls opposite the direction of the strike. Contrary to our predictions, snakes maintained high performance on open platforms by imparting rearward momentum to the posterior body and tail. This compensatory behavior increases robustness to changes in their strike conditions and could allow them to exploit variable environments.

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology during our centenary year, but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Derek Jurestovsky is an author on ‘ Blood python (Python brongersmai) strike kinematics and forces are robust to variations in substrate geometry’, published in JEB. Derek conducted the research described in this article while a PhD student in Henry Astley's lab at University of Akron, USA. He is now a Postdoctoral Scholar in the lab of Jonas Rubenson and Steve Piazza at Pennsylvania State University, USA, investigating squamate skeletal morphology, biomechanics and their distributions in the past, present and future.

Beberapa jenis ular eksport asal Indonesia yang mendapat perhatian dunia adalah Python reticulatus (sanca sawah), dan kelompok “sanca gendang” yaitu: P. curtus (sanca ekor pendek) dan P. brongersmai (sanca darah). Ketiganya masuk dalam daftar Apendik II CITES. Salah satu permasalahan dalam memahami kondisi populasi di alam pada kelompok reptil ini adalah luasnya habitat dan letak geografis, selain dari sifat satwa itu sendiri yang tidak memungkinkan dilakukan sensus secara terstruktur dalam satu satuan waktu yang pendek. Untuk itu perlu dilakukan suatu kajian tidak langsung yang dapat menjadi indikator penting mengenai kondisinya di alam. Tujuan penelitian ini adalah mengetahui karakteristik dan produksi dari kegiatan pengumpulan sanca sawah dan gendang di daerah Sumatera Utara. Penelitian dilakukan pada bulan September 2008 dengan metode survei terstruktur secara snow ball technique. Survei dilakukan dengan menelusuri para pengumpul daerah, agen serta masyarakat penangkap satwa liar dari mulai daerah Nangro Aceh Darusalam hingga Rantau Prapat. Hasil penelitian menunjukkan bahwa kegiatan penangkapan ular di wilayah Sumatera merupakan suatu kegiatan yang melibatkan cukup banyak anggota masyarakat. Secara kualitas, kemungkinan telah terjadi penurunan pada ular P. reticulatus, tetapi belum begitu tampak pada ular P. brongersmai dan P. curtus. Namun dari segi populasi tangkapan untuk semua kelompok ular tersebut ada kecenderungan penurunan dibandingkan dengan masa sepuluh tahun yang lalu, walau secara kuantitas masih perlu dilakukan perhitungan yang lebih mendalam lagi.