The Indian Gerbil

"A Vehicle of Lord Ganesh"

Introduction

The Indian Gerbil (Tatera indica), also called "The Antelope Rat", is the commonest gerbil in the Indian sub-continent. It occupies the sandy plains and grasslands of India, Sri Lanka, Pakistan and extends into southern Iran and as far west as Iraq, Kuwait and eastern Syria. To the north Indian Gerbils extend into Afghanistan and Nepal.

It is one of the largest species of gerbil, up to 430mm long from head to the tip of the tail. The tail is slightly more than half of the total length. It is reddish brown to fawnish grey in colour and has a whitish belly. There are light coloured or white spots above and behind the eyes and ears and on the sides of the nose. The tail is dark on both the top and bottom surfaces and has a light brown band down each side. There is a small black tuft at the tip. The fur of the body is long and thick. That on the tail is sparse, only just covering the scales of the tail. The soles of the feet are hairless, as are the long ears, which are usually over 20mm in length. Adults generally weigh between 100 and 227g. Males are normally a little larger than females.

Habitat

This gerbil's preferred habitat is almost anywhere that is not too sandy, or too cold. For example, the limit of their habitation matches closely the southern limit of winter frosts. Although dry plains are preferred, there is almost no type of habitat that these gerbils will not occupy if there is suitable food.

In India, Indian Gerbils are very common in areas of human habitation and in Iraq and Syria it is almost only found near villages. In Iran they live more remotely in areas with green vegetation all year round. In Afghanistan they are found near to isolated buildings on the edges of semi-desert areas and in dry stream beds. As high altitude brings colder temperatures they become rarer as the ground rises. In true desert areas such as Rajasthan they avoid shifting sand dunes and prefer the firmer plains.

In India burrows of Indian Gerbils have been found alongside main streets in the towns, and even in the granaries of the major cities of Pakistan. In Indian Villages they often burrow into hedgerows and mud walls that border the fields.

In the deserts of Northwest India the Indian Gerbil often lives alongside the Indian Desert Gerbil (Meriones hurrianae). This species prefers drier, sandy habitats. The difference between the two species can be seen by the way that M. hurrianae is more common in cultivated fields that are not irrigated, whilst T. indica is more common where the fields are irrigated.

Diet

Indian Gerbils are omnivorous and will readily eat insects and meat if offered. Outside the monsoon season Indian Gerbils eat mainly seeds supplemented by leaves, roots and insects. As the supply of seeds drops during the period of rains the number of available insects increases and the gerbils take advantage of this by increasing the proportion of these they take in their diet until if forms a significant percentage (40%). Indian Gerbils have been known to kill and eat smaller mammals, they also will live in orchards feeding on the seeds of the trees and the growing saplings.

Behaviour and Ecology

Gestation is 26-30 days. Four to six young open their eyes at 14 days. The young are independent at 21-30 days and reach sexual maturity in 10-16 weeks. The number of Indian Gerbils vary for month to month. Numbers are lowest in January, but increase steadily from March onwards by as much as 250% in September. This means that the population reaches its peak during the months of Monsoon. The Indian Desert Gerbil does the opposite with the highest numbers being in the driest months around January. In the wild the Indian Gerbil breeds all year round but peaks in February, July, August and November. The oestrus cycle is just under five days. Litter size is 1-10 with five or six being most common.

Tatera Indica are adventurous creatures and are very easy to trap. On one occasion researchers found seven gerbils in a single trap that was only 300x150x150mm and had not even been baited. On release, several of these gerbils had again been trapped within half an hour.

This gerbil can be a serious pest in areas where grain is stored or processed. They are dreaded by farmers because of the damage they do to crops by feeding on sown seeds, sprouts, mature plants and the ears of corn. They will fell standing corn to get at the seed heads.

Because of the terrible damage that Indian Gerbils do to the crops of poor farmers a lot of effort goes into studying this species and finding ways of controlling the population. On the other hand, the large number of insects eaten by Indian Gerbils in the south of India is considered by some researchers to make their presence a net benefit to mankind.

Indian Gerbils are very nocturnal and do not normally move far from their burrows. Sixty meters being the furthest observed in one study with many gerbils not moving more ten metres.

They live in loose communities. Each gerbil has a home range, but these ranges freely overlap with those of other gerbils. Except when raising young each burrow normally is occupied by one gerbil who will defend it against intruders. But in an emergency a gerbil will take temporary refuge in a neighbouring burrow. Although they live in their own burrow Indian Gerbils engage in social activity with other gerbils, they will chase, box and wrestle.

Indian Gerbils produce simple burrows. Usually consisting of several entrances drooping steeply down one to three feet to a single chamber. Burrows often have a "bolt hole". A tunnel ending a few millimetres from the surface. In an emergency the gerbil can break through this thin crust of soil and escape from the burrow if cornered.

Predation is mainly by birds of prey such as owls and kites. The Asian Jackal (Canis aureus aureus) will sometimes hunt gerbils although it prefers hares and larger mammals. Although snakes and monitor lizards will sometimes take gerbils, as will cats and foxes, studies of stomach contents show that gerbils are only very rarely taken by these animals.

Females, and even older youngsters, can be cannibalistic. Especially if disturbed when the litter is very young. Being a very aggressive species with known carnivorous tendencies it is thought that in the wild large numbers of young are killed by other Indian Gerbils when they first leave the burrow.

In Captivity

The Indian Gerbil was once widely kept in the UK but fell from grace when the Syrian Hamster became a common pet in the 1950s. A few have appeared in captivity in this country and Northwest Europe in recent years. Some have even found their way into zoological collections. In captivity they have been kept successfully on a dry mix diet supplemented with green vegetables. They have been known to live up to seven years in captivity. I have heard people say they are an easy to handle and tame animal, although a little nervous when raising a litter. However, the ones I once saw in The Netherlands seemed timid and looked like they would bite first and ask questions afterwards

And Finally

In Southern India and Ceylon the Indian Gerbil is dug out of its burrows as a source of food, but in the north the animal is thought too small to be worth eating. The Indian Gerbil is also taboo to many Hindus as it is considered "A vehicle of Lord Ganesh".

This image of the Hindu deity, Ganesha, "The remover of obstacles", taken from Mohan's Hindu Image Gallery, shows, at his feet, his "vehicle", or sign, a small rodent known as Mooshika Vaahana.

References

RODENTS OF ECONOMIC IMPORTANCE IN INDIA, Barnett S A, Prakash I, Arnold - Heineman, 1975

THE MAMMALS OF ARABIA (Second Edition), Harrison DL, Bates PJJ, Harrison Zoological Museum Publication, 1991

THE HANDBOOK OF RODENTS IN CAPTIVITY, Henwood, Chris, 1985

THE MAMMALS OF INDIA, Jerdon T C, Thomason College Press, 1867

MANUAL OF THE MAMMALS OF SRI LANKA. PART I-III. 2nd Revised Edition, Phillips, W.W.A., Wildlife and Nature Protection Society of Sri Lanka, 1980

RODENTS IN DESERT ENVIRONMENTS, Prakash, L and Gosh, P.K. (volume editors)., Dr W. Junk b.v. Publishers, The Hague., 1975, 90 6193 080 4 (Chapters III, IV, V and X)

THE BOOK OF INDIAN ANIMALS, Prater, S.H., Bombay Natural History Sci, 1980

THE MAMMALS OF PAKISTAN (REVISED EDITION), Roberts, T.J., Oxford University Press, 1997