ZooNooz Article - June 2005

More monkey business

Many people know that there are different types of monkeys, but would look at you blankly if you asked them what a langur is, writes NICK de GRAAFF.

Photographs Jo Nevin
Illustration Vicki Mike

Langurs, which are also known as Leaf Monkeys, are a distinct line of primates found mainly in Asia, and together with their better known cousins, the macaques and baboons, are part of the Old World Monkey group. Although the term 'langur' may be unfamiliar, there are some species which are commonly known. The Proboscis Monkey of Indonesia, famous for its unusually large nose, is one such example. Another is the Hanuman Langur of India, the representative species of the Monkey God.

Langurs are folivores - animals which specialise in eating leaves and other plant material. The Snub-nose Monkeys of China have even gone as far as specialising in eating lichens as they are the only plants available during the winter!

Langurs

Another species, the Francois' (pronounced Fran-swah) Langur hails from northern Vietnam and south-central China. Although many langurs occur in the same region, most are physically distinct from one another. Francois' Langurs have a pointed crest of hair on the head, and white 'sideburns' extending from the corners of the mouth to the top of the ear which contrast with their otherwise entirely black colour. They are unofficially classified as 'limestone' langurs, as they live their entire lives on flat limestone cliff-faces. Their days are generally spent travelling around their territory eating what vegetation they can find, but at sunset they return to their regular 'sleeping caves' for warmth and protection.

Until recently, little was known about langurs, and it is only in the last 15 years that we have gained enough knowledge and skill to allow such animals to be successfully kept in captivity - and just in time too. The homes of these primates are inaccessible and physically dangerous for humans to get to, so it's no wonder they are seldom seen and relatively unstudied. Francois' Langurs were believed to be safe from threat of poaching and habitat loss as they are fairly widespread over a large geographical area. However, 'widespread' populations are not the same as 'large' populations, and a census taken last year showed that sadly there are as few as 700 to 1000 individuals left in the wild.

Looking after langurs

Langurs

Captive management of langurs is significantly different to that of other primates, due to their specialised leafeating nature. Two such differences are worth mentioning. First, to maintain a healthy gut system, they eat leaves which are high in fibre and low in sugar. Like cows, langurs have large, partially chambered stomachs to hold the large quantities of leaves they must eat, and they rely on the bacteria present in the stomach to break the leaves down and unlock the nutrients inside. Unfortunately, commercially grown foods provide just the opposite, being low in fibre and high in sugars. High sugar levels can cause large fluctuations in the bacterial populations due to fermentation, and this can lead to severe gastric illnesses.

The second trait is their habit of eating anything that seems edible. They must maintain a slow and constant intake of food throughout the day to ensure that the bacterial levels remain constant. In captivity, this requires high resource management to ensure that this behaviour is catered for. In the past, this trait has conflicted with traditional zoo-keeping routine and many langurs turned to eating materials such as natural but indigestible fibres.

Taronga Zoo is again breaking new ground by being the first zoo in the region to add the Francois' Langur to its collection. Well-managed routines and specific diets, designed by keepers and veterinarians, see the first langur pair, Hanoi and Saigon from Nagoya Zoo in Japan, settling in well in preparation for their new home at the Asian Elephant Rainforest. These two will act as the founders for the new Francois' Langur breeding program in Australasia.

The specialised habitat and diet of the Francois' Langurs are not their only unique characteristics. Langurs are also famous for their bright golden-coloured offspring. Living in harem societies, the females give birth around the same time, and all babies are born the same colour. The big contrast between baby and adult colouration is commonly believed to promote the mothering instinct in all females of the harem. It is a regular occurrence that a female will happily care for an orange-coloured infant, even if it is not her own. This allows the real mother time to forage for a meal of her own or simply have a break. Soon, Taronga hopes to have such colouration in its own langur group, as not only does it serve as an amazing sight for visitors, it also serves as a good indication of the future survival of the Francois' Langur population.

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