Tuesday, January 19

Much maligned macaques

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The long tailed macaque is an opportunistic omnivore, eating a great variety of plants and animals.

MACAQUES are monkeys and not apes. My dealings with them have been confined to the Southeast Asian countries of Cambodia, Malaysia, Myanmar, Singapore, and Thailand, not to mention Mauritius and Japan. They have learned to live with man and have become invasive in that they steal fruit from street vendors’ stalls, rummage through litterbins, hold traffic up when a troop decides to cross a road, as well as invading villagers’ houses in search of food. I have witnessed the best of them in nurturing their babies and of the most vicious attacks by them.

In the late 1990s, my late wife and I were frequent visitors to Sabah and Sarawak. One day we explored the island of Sapi in the Tunku Abdul Rahman Park and on our trek to the lookout point, we encountered a troop of macaques who would not let us get to our destination and angrily advanced towards us. We hurriedly beat a retreat only to run into a swarm of mosquitos! Another time, on the same island, whilst we were snorkelling, a lone macaque rummaged through our beach bags and stole my wife’s sunglasses and sat brazenly up a nearby palm tree trying them on. After an hour of trial and error he discarded them! It was on our visit to Bako National Park, upon seeing a slow loris, we were invaded by a roaming pack of bared teeth macaques and we ran for our lives with them snapping at our heels.

Species of macaque

Worldwide there are 23 different species which live in a variety of climates and habitats ranging from Southeast Asia, Sri Lanka, India, Pakistan, Afghanistan, Japan, Northern China, Nepal, Morocco, and Gibraltar. Of the 23 species, four are found in Malaysia: the southern pig-tailed ‘berok’, the stump-tailed, the crab-eating or long-tailed ‘kera’, and the Rhesus macaque. The local names of ‘berok’ and ‘kera or kra’ are given to species and represent their shouts.

Macaca fascicularis

The Latin name for the crab-eating or long tailed macaque is attributed to Sir Thomas Raffles in 1821. With a dark brown upper body and underparts of light grey and a dark greyish brown tail, the males weigh between 5kg and 9kg and the females at between 3kg and 6kg. Their tails are longer than their bodies, usually 40cm to 60cm in length, whilst their bodily length is between 35cm and 55cm. By comparison their arms and legs are relatively short. The males are distinguished by their moustaches, cheek whiskers, and bushy white eyebrows, whilst the females, also with cheek whiskers have foregone moustaches!

Their lives

Living in social groups of up to 20 females with one or several males, there is social hierarchy dominated by the matriarch of the pack and an alpha male. It is thought that living in such a large pack that there is strength in numbers and protection from predators. Females have their highest birth rates at 10 years of age and cease bearing young at 24. The gestation period ranges from 162 to 193 days, giving birth to a single baby of 320 grams. These macaques practise a form of population control when high ranking females kidnap the infants of low ranking females. Because the elderly matriarchs are not lactating, the babies die.

Main sources of food

Its name is somewhat misleading, for it is an opportunistic omnivore, eating a great variety of plants and animals. Fruit and seeds constitute up to 90 per cent of its diet and it also eats bark, flowers, leaves, and roots. Sometimes it steals birds’ eggs and chicks from their nests and devours fish, frogs, and lizards. However, it is a proficient swimmer, diving in mangrove swamps for crabs. With a penchant for wild durians, it spits out the seeds thereby dispersing them to other areas.

A menace to lowland farmers, long tailed macaques often feed on young rice, cassava, rubber fruit, taro, coconuts, and mangoes. Perhaps their greatest threat to mankind is that they may carry potentially fatal human diseases such as the Herpes B virus and Plasmodium knowlesi, which causes malaria.

Scientific research

Whilst this species is revered in some temples in Southern and Southeast Asia, it is of particular scientific importance as both humans and this breed of monkey can share infections because of their close physiology. Thus, this breed is frequently used in medicinal disease experiments. In remote areas of our planet these animals are hunted for bush meat. In the 2020 International Union for Conservation of Nature report, the long-tailed macaque was downgraded to least concern because of its ability to adapt to different habitats and should not be kept as a domestic pet.

Macaca nemestrina

I have only once witnessed the southern pig-tailed macaque at Sepilok in Eastern Sabah. This medium sized macaque lives in Southern Thailand, Malaysia, and in the Indonesian provinces of Sumatra and Kalimantan. Appropriately, its name nemestrina is a derivative of a Latin word meaning ‘the god of groves’. The males weigh up to 14.5kg and the females up to 11kg, with both sexes possessing an average height of approximately 52cm. Their fur is olive brown in colour apart from their undersides, which are white. Their short curved tail is carried erect thus resembling a pig’s tail. With an average life span of 26 years, the males sport large incisor teeth, which they use to good effect when threatened by an aggressor.

Ecology

These monkeys are omnivorous, feeding on berries, fruit, rice seeds, and fungi, and often raid crops during rainstorms when the farmers are inside. In some areas of Malaysia, farmers keep and train pig-tailed macaques to fetch coconuts and pick fruit from cultivated trees. They supplement their diet by eating insects, small lizards, and birds. Likely invaders of oil palm plantations, there the pig-tailed macaques feed on rats, killing them at an annual rate of 70 rats per monkey. This saves the owners great expense for over 10 per cent of palm oil crops are damaged by rats eating the fruit. A new light has been cast upon southern pig-tailed macaques for instead of being a pest, they can now be seen to be efficient pest-controllers. This has encouraged plantation owners to boost the habitat of macaques around the oil palm plantations.

Foraging and hierarchy

Living in packs of up to 80 monkeys, in order to forage they split up into smaller subgroups of up to six. As they move they keep in contact with other subgroups by shouting ‘brok’. Again, an alpha male dominates the pack but the leader of the pack is an alpha female. Sexual maturity is reached after three to five years with a gestation period of usually five months. A female produces one infant every two years.

Whatever you may think about the kleptomaniac and aggressive tendencies of both the crab-eating and pig-tailed macaques, both species serve man well. The former used for medicinal testing and the latter as an unpaid rodent killer and fruit gatherer.