Bornean tiger

The Bornean tiger is possibly an extinct tiger population that is thought to have lived in the Sunda island of Borneo in prehistoric times.[1][2] While a live Bornean tiger has not been conclusively recorded, indigenous people believe in its existence.[3][4]

Painting in Kuching, Sarawak, Malaysian Borneo

Archaeological records and cultural views
Relief on a Chinese Buddhist temple at Kuching
Chinese-style relief of a warrior riding a tiger in Semenggoh Nature Reserve, Sarawak

Archaeological excavations in Sarawak and Sabah produced an upper canine tooth, a navicular and a metacarpal bone that were identified as being of a tiger. It has therefore been suggested that the tiger was present in Borneo during the late Pleistocene and early Holocene.[5] A bone fragment was also found in the Philippine island of Palawan. Archaeologists considered it unlikely that these fragments were traded between different regions during the Pleistocene. Natives of Borneo keep the memory of the tiger alive in their culture by treating its body parts as heirlooms. Therefore, it has been suggested that the Bornean tiger existed longer than prehistoric times.[6]

Possible connection with Palawan

Borneo might have been connected to Palawan during the penultimate and previous glacial periods, judging from the molecular phylogeny of murids.[7] In northern Palawan, two articulated phalanx bones, possibly from the same toe, besides a distal segment of a basal phalanx (ICWM-2376) of the 5th or 4th digit of the pes or manus, were excavated amidst an assemblage of other animal bones and stone tools in Ille Cave near the village of New Ibajay, in the province of El Nido. One bone (IV-1998-P-38239) was a full basal phalanx of the second digit of the left manus, and the other (IV-1998-P-38238) was the distal portion of a subterminal phalanx of the same digit and manus. With the former bone having a greatest length of 46.44 mm (1.828 in), and the latter having a medio-lateral width of the distal end of 16.04 mm (0.631 in), for example, their measurements were similar to those of extant tigers from the Malayan Peninsula and India. The other fossils were identified as being of the Philippine long-tailed macaque, the Philippine deer, the Palawan bearded pig, small mammals, lizards, snakes and turtles. From the stone tools, besides the evidence for cuts on the bones, and the use of fire, it would appear that early humans had accumulated the bones.[6] Additionally, the condition of the tiger subfossils, dated to approximately 12,000 to 9,000 years ago, differed from other fossils in the assemblage, dated to the Upper Paleolithic. The tiger subfossils showed longitudinal fracture of the cortical bone due to weathering, which suggests that they had post-mortem been exposed to light and air. Tiger parts were commonly used as amulets in South and Southeast Asia, so it may be that the tiger parts were imported from elsewhere, as is the case with tiger canine teeth, which were found in Ambangan sites dating to the 10th to 12th centuries in Butuan, Mindanao.[7][8]

On the other hand, the proximity of Borneo and Palawan also makes it likely that the tiger had colonized Palawan from Borneo in the Middle Pleistocene, about 420,000–620,000 years ago,[6] during periods in which relative sea levels decreased to their lowest, at ca. −130 m (−430 ft), by the expansion of ice sheets.[9][10][11]

Considering the ability of tigers to swim,[12] it is possible that the tiger crossed the Balabac Strait when the distance between the islands of Borneo and Palawan was much less than today,[6] during the Middle and Late Pleistocene, before the Last Glacial Maximum circa 18,000 years ago.[13][14]

Twelve non-volant mammals in Palawan have close relatives in other islands of the Sunda Shelf, including Borneo.[15] Thus the Palawan is considered to be the northeastern part of the biogeographic region of the Sunda Islands. It is believed that Palawan had a landmass of approximately 100,000 km2 (39,000 sq mi), when the sea was 120 m (390 ft) lower than at current levels during the Last Glacial Maximum, and that the climate was dry and cool compared to now,[16] with open woodland mostly constituting the vegetation, except perhaps for a few savannahs. Palawan was inhabited by a number of arboreal and terrestrial animals, such as pigs and deer, as indicated by an archaeozoological study of Ille Cave.[6]

At the end of the Pleistocene, the Balabac Strait widened due to the amelioration of the climate and subsequent rise of the sea level. The widening of the strait would have isolated the Palawan tigers and narrowed their available territory. The rise in sea level was such that almost 90% of Palawan got inundated, and its total landmass reduced to less than 12,000 km2 (4,600 sq mi), by around 5,000 years ago. Moreover, in the early Holocene, closed canopy rainforest would have replaced the open seasonal woodland and savannah.[14][16] As indicated by the Terminal Pleistocene archaeozoological record from Ille Cave, climatic and environmental change, besides predation by humans, put pressure populations of deer, which were likely important resources for the tiger. The number of deer thus declined after 5,000 years ago, and before the start of historical records.[17][18] To put it simply, a significant decrease in habitat and food resources, isolation from other populations by increasing sea levels, and possibly hunting by humans likely caused the extinction of the Palawan tiger population, just as these or similar factors threaten existing populations of tigers. To date, no evidence exists for the tiger surviving in Palawan beyond 12,000 years ago.[6]

Characteristics

It has been assumed that the Bornean tiger might have been rather small in size, similar to the Sumatran tiger.[19] According to the native people, this tiger is bigger than a clouded leopard, and largely brown in colour with faint stripes.[3]

Behaviour and ecology

Borneo is home to species that the tiger would prey on, such as the Bornean bearded pig, the Bornean yellow muntjac and the sambar. According to the natives, unlike the sympatric Sunda clouded leopard, the tiger did not climb trees.[3]

Alleged records

Sightings in the late 20th century have been alleged. In 1975, Douchan Gersi claimed to have seen a tiger in East Kalimantan. He took two photographs of the animal.[20] These photos depict a tiger, but its origin remains unclear,[3] and the authenticity of the photographs was doubted.[1] It might have been an escaped captive one.[20] In 1995, native people in Central Kalimantan claimed to have heard a tiger roar, and that they were able to distinguish between a tiger's roar and vocalisations of other animals.[3]

See also

References
  1. Medway, L. (1977). "The Niah Excavations and an Assessment of the Impact of Early Man on Mammals in Borneo" (PDF). Asian Perspectives. 20 (1): 51–69.
  2. Medway, L. (1977). Mammals of Borneo: field keys and an annotated checklist. Kuala Lumpur: Malaysian Branch of the Royal Asiatic Society No. 7.
  3. Meijaard, E. (1999). "The Bornean Tiger; Speculation on its Existence". Cat News. No. 30. pp. 12–15.
  4. Kitchener, A. C.; Yamaguchi, N. (2010). "What is a tiger? Biogeography, Morphology, and Taxonomy". In Ronald Tilson; Philip J. Nyhus (eds.). Tigers of the world: The Science, Politics and Conservation of Panthera tigris. Cambridge: Academic Press. pp. 59–81. ISBN 978-0-8155-1570-8.
  5. Piper, P. J.; R. J. Rabett, Earl of Cranbrook (2007). "Confirmation of the presence of the tiger Panthera tigris (L.) in Late Pleistocene and Holocene Borneo". Malayan Nature Journal. 59 (3): 259–267. Retrieved 2018-05-29.
  6. Piper, P. J.; Ochoa, J.; Lewis, H.; Paz, V.; Ronquillo, W. P. (2008). "The first evidence for the past presence of the tiger Panthera tigris (L.) on the island of Palawan, Philippines: extinction in an island population". Palaeogeography, Palaeoclimatology, Palaeoecology. 264 (1–2): 123–127. Bibcode:2008PPP...264..123P. doi:10.1016/j.palaeo.2008.04.003.
  7. Van der Geer, A.; Lyras, G.; De Vos, J.; Dermitzakis, M. (2011). "15 (The Philippines); 26 (Carnivores)". Evolution of Island Mammals: Adaptation and Extinction of Placental Mammals on Islands. John Wiley & Sons. pp. 220–347. ISBN 9781444391282.
  8. Ochoa, J.; Piper, P. J. (2017). "Tiger". In Monks, G. (ed.). Climate Change and Human Responses: A Zooarchaeological Perspective. Springer Publishing. pp. 79–80. ISBN 978-9-4024-1106-5.
  9. Rohling, E. G.; Fenton, M.; Jorissen, F. G.; Bertrand, P.; Ganssen, G.; Caulet, J. P. (1998). "Magnitudes of sea-level lowstands of the past 500,000 years". Nature. 394 (6689): 162–165. Bibcode:1998Natur.394..162R. doi:10.1038/28134. S2CID 4421184.
  10. Waelbroeck, C.; Labeyrie, L.; Michel, E.; Duplessy, J. C.; McManus, J. F.; Lambeck, K.; Balbon, E.; Labracherie, M. (2002). "Sea-level and deep water temperature changes derived from benthic foraminifera isotopic records". Quaternary Science Reviews. 21 (1): 295–305. Bibcode:2002QSRv...21..295W. doi:10.1016/S0277-3791(01)00101-9.
  11. Bintanja, R.; Van de Wal, R.S.W.; Oerlemans, J. (2006). "Modelled atmospheric temperatures and global sea levels over the past million years". Nature. 437 (7055): 125–128. Bibcode:2005Natur.437..125B. doi:10.1038/nature03975. PMID 16136140. S2CID 4347450.
  12. Nowell, K.; Jackson, P. (1996). "Tiger" (PDF). Wild Cats: Status Survey and Conservation Action Plan. Gland, Switzerland: IUCN/SSC Cat Specialist Group. pp. 55–64. ISBN 978-2-8317-0045-8.
  13. Voris, Harold K. (2000). "Maps of Pleistocene sea levels in Southeast Asia: Shorelines, river systems and time durations". Journal of Biogeography. 27 (5): 1153–1167. doi:10.1046/j.1365-2699.2000.00489.x.
  14. Bird, M. I.; Taylor, D.; Hunt, C. (2005). "Palaeoenvironments of insular Southeast Asia during the Last Glacial Period: A savanna corridor in Sundaland?". Quaternary Science Reviews. 24 (20–21): 2228–2242. Bibcode:2005QSRv...24.2228B. doi:10.1016/j.quascirev.2005.04.004.
  15. Esselstyn, J. A.; Widmann, P.; Heaney, L. R. (2004). "The mammals of Palawan Island, Philippines". 117 (3). The Biological Society of Washington: 271–302. Cite journal requires |journal= (help)
  16. Heaney, L. R. (1991). "A synopsis of climatic and vegetational change in Southeast Asia". Climatic Change. Climate Change. 19 (1): 53–61. Bibcode:1991ClCh...19...53H. doi:10.1007/BF00142213. S2CID 154779535.
  17. Fox, R. (1970), The Tabon Caves, Manila: The National Museum of the Philippines
  18. Lewis, H.; Paz, V.; Lara, M.; Barton, H.; Piper, P.; Ochoa, J.; Vitales, T.; Carlos, J.; Neri, L.; Robles, E. C.; Padilla, R.; Ragragio, A.; Solheim, W. II.; Ronquillo, W. (2008), Dating and interpreting Early to Middle Holocene cave occupation and an early cremation burial from Palawan, Philippines, 82, Antiquity, pp. 318–335
  19. Kitchener, A. C. (1999). "Tiger distribution, phenotypic variation and conservation issues". In Seidensticker, J.; Jackson, P.; Christie, S. (eds.). Riding the Tiger: Tiger Conservation in Human-Dominated Landscapes. Cambridge University Press. pp. 19–39. ISBN 0521648351.
  20. Gersi, D. (1975). Dans la jungle de Bornéo (in French). Paris: Éditions G. P.
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