Читать книгу Tropical Wildlife - Jane Whitten - Страница 6

Orangutans

These large, red, long-haired apes are found in the forests of lowland North Sumatra and Borneo. The impressive adult male, with cheek flanges of fibrous tissue accentuating his face, can weigh up to 90 kg. Females are smaller, weighing only 40-50 kg.

These diurnal apes spend most of their time in the trees. They live on fruit, some of which is poisonous to humans, supplemented by leaves and shoots, but will also eat eggs and small animals. Their detailed knowledge of the forest enables them to search very efficiently for fruiting trees. Orangutans travel by holding on with their hook-like hands and feel, using their weight to swing trees back and forth to narrow a gap so that they can reach the next tree. Travel is cumbersome, and they go only a few hundred meters each day, fashioning branches into a treetop nest at dusk. Older, heavier males may resort to traveling on the ground, giving rise to stories of wild forest men.

Orangutans are largely solitary, although young animals sometimes play together. Females mature at ten years and may have three or four offspring during their lifetimes, weaning them at about three years. Juveniles finally leave their mothers at 7-10 years of age. Adult males defend those females within their range from other males, advertising their presence by calling, displaying aggressively when they meet and occasionally even fighting.

These animals are extremely strong and able to crack hard forest fruits easily, but are also dexterous and very curious. A camera inadvertently left behind, which caught the attention of wild orangutans, was later found totally dismantled. Nothing was broken.

Orangutans are threatened by habitat loss and hunting, as females are sometimes killed to obtain infants for the pet trade. However, large reserves in Indonesia and Malaysia contain good populations of orangutans, and a prolonged campaign of public education has lessened the pet trade.

Orangutan, Pongo pygmaeus

Gibbons

There are nine species of gibbon in the forests of Southeast Asia. Eight of these species weigh around 6 kg, and the larger siamang weighs about 10 kg. The smaller species arc geographically separated by seas and rivers, but the siamangs overlap with them in the forests of Peninsular Malaysia and North Sumatra. Gibbons are uniquely adapted to life in the forest canopy and are almost never found on the ground. They travel quickly and efficiently by swinging from branch to branch, often leaping between supports. The siamang's diet consists almost equally of fruit and leaves, while the smaller gibbons eat mainly fruit, which they pick carefully, leaving unripe fruit to ripen. They also eat leaves, shoots and insects.

Gibbons live in monogamous families into which a single offspring is born every two or three years. Infants are weaned in their second year, but stay with their parents until they are about eight. In siamang groups, the male takes care of the infant after the first year.

A gibbon family lives within a well-defined home territory, which the animals know well, visiting trees as they come into fruit. A gibbon group travels about 1.5 km in a day whereas the larger siamangs travel less than a kilometer. The groups sleep in tall, emergent trees, safe from predators. Before dawn, the males of some species sing to advertise the presence of the group and their occupancy of that area of forest, About a third of the active day is spent feeding and another third traveling between feeding trees.

Siamang groups are very cohesive, with individuals rarely more than 10 m from each other, whereas individuals in a group of small gibbons are more spread out, coming together to feed in larger fruiting trees. Adults groom each other, which helps maintain the pair bond. Most gibbon pairs also perform an elaborate duet that lasts for about 15 minutes. These stereotyped songs differ between species and are thought to advertise the presence of a pair in the territory and to reinforce pair bonding.

Mentawai gibbon, Hylobates klossii

Javan gibbon, Hylobates moloch

Siamang, Hylobates syndactylus

Müller's gibbon, Hylobates muelleri

Proboscis and other

Leaf Monkeys

Leaf monkeys are found through most of Southeast Asia although some species, like the proboscis monkey, have very restricted ranges. Most are relatively slender monkeys with long tails and largely arboreal lifestyles. The species are distinguished by coat color and hair patterns on the head.

Some leaf monkeys eat nothing but leaves, but most eat flowers, buds, seeds and shoots as well. They have complex stomachs, with bacteria-filled fermenting chambers that break down leaves, releasing the normally indigestible sugars and deactivating the leaf toxins. Because the leaf monkey eats such poor quality food, it has to forage for much of the day, and its stomach contents may constitute a quarter of the animal's weight.

Leaf monkeys live mostly in large groups comprising one male and a number of females with their offspring. An infant is born with its eyes open and is strong enough to hold onto the mother's fur while she travels. Females frequently tolerate and even suckle each other's Small infants, Excess males form groups and look for opportunities to take over from breeding males. Incoming males usually kill all the infants fathered by their predecessors, although the mothers sometimes manage to protect their infants.

The proboscis monkey is found only in the coastal swamp forests of Borneo. The males have remarkable faces, with long pendulous noses, the functions of which have long been the source of speculation. In the past, suggestions have been made that they enable the large male to give off heat or that the noses assist in swimming by acting like some kind of snorkel. It is now thought that they serve to attract females, like the peacock's tail. Proboscis monkeys feed mostly on young leaves and travel further than most forest monkeys to obtain this scarce food. These monkeys swim well and cross large rivers very quietly, with no splashing that could attract crocodiles.

Silvered leaf monkey, Semnopithecus cristata

Female and juvenile proboscis monkey, Nasalis larvatus

Male proboscis monkey, Nasatis larvatus

Banded leaf monkey, Presbytis melalophos

Javan leaf monkey, Presbytis comma

Macaques

Macaques are the typical monkey—gregarious, active and curious. They are primarily fruit eaters, but will also eat other plant parts and small animals, from insects to birds and mammals, if they can catch them. Where they come into contact with people, they will expand their diets to include garbage, peanuts and other offerings, or stolen crops. They spend more time on the ground than the leaf monkeys, but are excellent climbers and swimmers.

Macaques are long-lived and give birth to a single infant each year, after a gestation of five or six months. The infant is born with fur and open eyes, and can immediately travel clinging to its mother's belly fur, with a nipple in its mouth to support its head. Nursing becomes infrequent after the first few months, but usually continues until the next infant is born. These social animals spend long periods in mutual grooming, which helps reinforce group cohesion.

The long-tailed or crab-eating macaque is found in a variety of habitats, especially coastal forests and offshore islands where it frequents low trees and scrub. The pig-tailed macaque, named for the shorter tail which it carries curled over its back, is found more in inland hill forests. It is mostly arboreal, but is unique in that it will descend to the ground to flee from people. Pig-tailed macaques seem to learn more readily than other macaques, and captive pig-tails are trained throughout the region to pick coconuts. Experienced individuals are able to choose ripe fruit without help, while less experienced individuals are directed by their handlers. Both species are found in groups of up to forty individuals, but these large groups often split up to feed.

On the island of Sulawesi there are lour distinct species of macaque, all of which are found nowhere else. They all resemble the pig-tailed macaque, hut differ in fur pattern and color.

Booted macaque, Macaca ochreata

Long-tailed macaque, Macaca fascicularis

Black-crested macaque. Macaca nigra

Pig-tailed macaque, Macaca nemestrina

Lorises and Tarsiers

The slow loris is very appropriately named. This small, nocturnal creature prowls around the lower and middle canopy of mature or disturbed forest in search of fruit, nestlings and other small animals. It climbs very deliberately and slowly, walking hand over hand along the branches, one limb at a time and is able to remain motionless for hours on end. When catching an insect, the slow loris stands on its hind feet and throws its body forward with surprising speed, grabbing the animal with both hands and dispatching it with a bite from its sharp teeth.

Female lorises do not make nests, but give birth in the Open to a single young each year. The offspring is at first carried continuously, but is later parked on a branch for short periods while the mother hunts. The parents usually sleep close together and the young may be found clinging to either of them.

Tarsiers can be found in all sorts of habitats including towns, mangrove forests, secondary forests and montane forests. These tiny primates, weighing no more than 135 g, have enormous eyes. Each eye weighs a little more than the whole brain, giving them excellent night vision for hunting. They catch beetles, cockroaches, ants, birds and sometimes snakes by leaping at them and pinning them down with one or both hands, often on the ground,

Tarsiers are most active in the hour or so before dawn. The adults and their offspring head back to their sleeping sites in thickets among vine or fig tangles, or in tree holes, Just before retiring the family sings a complex call notifying all those with an interest in the matter that they are still alive and defending their one-hectare territory, the boundaries of which they will have marked out with drops of odoriferous urine during the night.

Slow loris, Nycticebus coucang

Slow loris, Nycticebus coucang

Western tarsier, Tarsius bancanus

Spectral tarsier, Tarsius spectrum

Wild Cattle