In lieu of an abstract, here is a brief excerpt of the content:

209 9  On the Edge Conservation and the Threat of Extinction The orangutan’s decline toward extinction began several thousand years ago, well before the start of human history. The red ape’s dwindling in numbers is underpinned by basic features of the animal’s biology. As with all apes, the natural reproduction rate of orangutans is slow.1 Females do not normally give birth before they are fifteen years old, and they typically have no more than four offspring in a lifetime, with intervals of several years between births. For tree dwellers with few natural predators, this basic biology is unproblematic and allows for the investment of time and energy in the socialization of a small number of children. Orangutans in the wild seem to have life spans of more than fifty years.2 The slow pace of reproduction, however, means that the loss of individuals through hunting or other catastrophe cannot quickly be made up. Both recently and in a very long historical perspective, moreover, the habitat of the orangutan has proven to be vulnerable. Tropical rain forest is a resilient ecological form, but its recovery from disruption is not swift, and local interruptions to food supply can be disastrous for a small orangutan population. The clearest putative ancestor of the orangutan is the extinct ape genus Sivapithecus , found in the north of the Indian subcontinent and dated to between twelve and eight million years ago. Fossil and subfossil remains of orangutans have been found in India, China, and Southeast Asia dating from the Pleistocene era, 2.5 million to 12,000 years ago, though there is no evidence that their range encompassed the whole of this area at any one time. We can only speculate about their place in the region’s ecology, but we know that there was more than one speciesoforangutanandmorethanonegenusofgreatapeintheregionandthatmany of the fossil and subfossil remains were of animals that appear to have been signifi- 210  Chapter 9 cantly larger than today’s orangutan. This evidence suggests that the orangutan, like the Australian koala and the New Guinea tree kangaroo, became arboreal in fairly recent evolutionary times, since large size is not an advantage at the top of a tree.Itispossiblethathuntingbypredatorssuchastigers,orthe greater availability of fruit in the trees, may have given evolutionary advantages to orangutans who could climb, but there is no fossil evidence to suggest the mechanism by which this shift to the trees took place.3 Twenty-five thousand years ago, orangutans were to be found in moist rain forest in the western Indonesian islands, over much of the Southeast Asian peninsula , and in adjacent regions in what is now eastern India and southern China.4 The sharp contraction of the range of the orangutan to the island of Borneo and a small area in Sumatra appears to be connected with habitat loss and probably also with hunting. Eighteen to twenty thousand years ago, the earth experienced its most recent ice age, during which the climate in Southeast Asia became colder and dryer with fewer habitats suited to orangutans. It is not known when orangutans became extinct in Java or in mainland Southeast Asia. Java’s dry season becomes more pronounced as one moves east, meaning that there are long periods with meager fruit supplies, so the orangutan was probably always restricted to the western half of the island. Under these circumstances local extinction was possibly caused by the eruption in AD 535 of a volcano called Kapi (very likely today’s Krakatau) in the Sunda Strait region.5 In any event, there is no recognizable trace of a folk memory of the orangutan in Javanese culture and nothing is represented in the abundant animal life depicted in carvings on Java’s Hindu and Buddhist templesthatcanplausiblybe interpretedas an orangutan.6 Logan reported in 1849 that local people in the Malay Peninsula used the term mawas to denote a “race of naked savages” in the interior.7 Since mawas is the common Sumatran term for the orangutan, it is not impossible that this usage reflected a folk memory of Pongo pygmaeus on the peninsula. The possible role of hunting in early extinctions is controversial because it potentially undermines the contemporary discourse describing indigenous peoples as traditional environmental custodians, but evidence from the Niah cave in Sarawak indicates that humans hunted and ate orangutans there 35,000 years ago. This region is now without this species.8 The dynamics and timing of extinction in China and mainland Southeast Asia are even less certain...

Share