Sunday, July 31, 2011

How many Primates are there in Sri Lanka?

by Uditha Wijesena
Field guides written for birds outnumber those written for Mammals. Sri Lanka lacks a mammalian guide. The last complete work probably is W. W. A. Phillips Manual of the Mammals of Sri Lanka in three volumes. But this is not a field guide as such.
Vivek Menon has done a wonderful book A Field Guide to the Indian Mammals. The book is a bit expensive, but I felt compelled to buy it. Having purchased my copy, the next task was to mark out those that occur in Sri Lanka. This was no easy task without a biologist's assistance. India has fifteen (15) primates while Sri Lanka has only four (4). Of this four, only two occur in India. They are the Slender Loris (Loris tardigradus) and the Hanuman Langur or Grey Langur (Semnopithecus entellus). The other two are endemic to Sri Lanka, the Toque Monkey (Macaca sinica) the Rilawa and the Purple-faced Leaf Monkey (Semnopithecus vetuls) or Helli Wandura. I'm sure many would not have known that the ordinary Rilawa and the Helli Wandura that exploits the mango and banana trees in the garden are found only in Sri Lanka. Let us see if we have done justice to them.
The Slender Loris is nocturnal and we know very little about it. The Hanuman Langur is widely distributed in the dry zone and still could be found in fairly plentiful numbers. They occur in all dry zone districts where many of our National Parks are located. Its food consists of fruits, flowers, leaves and grain.
During the dry parched seasons, one could find them seated among the men and women in dried up tank beds eating lotus seeds while the latter digs for lotus roots and legumes. Men seem to co-exist with this species in the dry zone unlike its counter part the Toque Monkey.
The Torque Monkey endemic to Sri Lanka and is widely distributed in the whole country and has a very unique ability to adapt to changing habitat conditions. Being omnivorous it is said that they predate even birds. Recently, they have turned out to be scavengers in most temple areas where people have got in the habit of feeding them. A prolific breeder the numbers have gone to intolerable levels and is now considered an agricultural pest, resulting it being poisoned by the dry zone peasant.
However even with these grave conditions their numbers don't seem to ring alarm bells to the conservationists. The Purple faced Leaf Monkey endemic to Sri Lanka is confined to the wet zone with its sub species the Bear Monkey in the hill country. This is the troubled monkey which happens to be competing with man for its habitat. Thirty years ago it was a common occurrence in the sub urban Colombo and in the wet zone villages. It was very common then to find them raiding home gardens in the fruiting season. Unlike the other monkey species in Sri Lanka this species is very selective in it's diet. Thus the rapid urbanisation has taken a toll on the numbers of these monkeys. The lower numbers in the troops has even resulted in the behaviour of the dominant male killing the young males to maintain harems.
It's a pity that we in our social development seem to have pushed this species in to extinction. It is now found mainly in the remaining rainforests in the wet zone. So next time you visit Sinharaja, if you hear the Purple-faced Leaf Monkey, look for it, for it may be the last time you might see it. That apparently is the number of primates in Sri Lanka.
How strange Sri Lanka has a national flower Nil Manel (Nymphaea stellata) a national tree Na (Messua ferrea) and a national bird the Sri Lanka Jungle fowl (Gallus lafayetii). Why not a national mammal endemic to Sri Lanka ? Can I propose the Purple faced Leaf Monkey as the national mammal endemic to Sri Lanka? 

Published in the Sunday Observer Environment  2004 - 6 - 27

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