Last Tuesday morning, we tried to catch a toque monkey which is hanging around our department in the faculty. That’s because Dr. Basil wanted to do a research on their reproduction. But the monkey escaped while we are preparing the dart.
There are 3 monkey species found in Sri Lanka. They are Purple face leaf Langur, Gray Langur and Toque Monkey. Among them Toque monkey is the more common one. Same time it has been the most trouble maker in the Sri Lankan society. They live in troops and they are found all over the country. for more details http://www.arkive.org/toque-macaque/macaca-sinica/ or http://en.wikipedia.org/wiki/Toque_Macaque.
These toque monkeys do sever damages to the crops and the properties of the Sri Lankan people all over the country. In some areas they have been a Menes to farmers. They even invade in to highly populated towns. Now it has become real trouble in Sri Lanka same as the Stray Dogs. Same time this is another side of the human animal conflict. Same time these monkeys very often attack human with no fear. So, it also has the risk of spreading Rabies.
Sri Lanka now got to face this problem. I have personally experienced this problem since my home is placed in an area where high numbers of these toque monkeys are found. They get in to houses even trough tiny opening and then they eat whatever they find, then grab some thing and run back in to trees. Some people in my area used to cut down the trees which situated very close to their houses. That’s because these monkeys jump in to roofs from these trees and that make big damage to the roof. People, they really suffer with this problem.
I think Sri Lanka still have not thought to find a solution for this problem. Poor people who suffer with monkey Menes try to find their own solution by killing these animals. I have experienced this situation around my place. Few months ago I found a Toque monkey lying down in a bush close to my place while I’m walking home. But, I didn’t care much because it is usual to see monkeys hanging around in that area. But, later I noticed that this monkey is not normal. Somehow it disappeared after some times. Next day I got to know that around 25 monkeys has died due to poisoning in previous day. That was done by a lady living in the area. I tried to find out why she did so. This troop of monkeys used to get in to the house of that woman. They have eaten the meal prepared for the lunch several days. So, this poor woman was very angry. So, she mixed some poison with the rice and kept next day. That’s how the woman got the solution for the problem. When the officials ask her she said that moneys have grabbed the bag of poisons which was brought to use for the crops.
Due to high population of these animals forests can’t handle the requirement of food for them. That’s why they invade in to villages. Same time the reduction of the area of forest has been another reason. Very soon Sri Lanka has to make a plane to manage this problem. As Dr. Basil said it is necessary to control the Toque monkey population of the Sri Lanka. Or else this will be a real headache to Sri Lanka and many animals will get killed by human as I mentioned above.
There is a program going on to control rabies by controlling the stray dog population Sri Lanka. In this program dogs are neutered (ovarian histo ectomys and castrations done) and vaccinated.
But to control monkey population we can’t use the same surgical method. Because, they have a different reproduction behavior. Toque monkeys live in troops and they have an alpha male or dominant male. This male is the strongest male in the troop. It is the animal which has the right to reproduce. In order to control the population we can capture the alpha male and neuter it and release back. But, we can’t castrate that animal. If the male is castrated, it will no longer have libido and it will be more like a female. As soon as that occur another male will become the alpha male and this animal will be chased out of the troop. So, that doesn’t work. So, we will have to do vasectomy to the captured alpha male and release. So, the animal still will be the dominant animal.
There are no enough researches done in this area. But, soon that should be done. Dr. Basil said he is going to do a research in this area soon.
Primate social behavior is very complex. More so than dogs. Even if the alpha is sterilized it will not stop reduce the reproduction rate, there are lots of other males around.
ReplyDeleteThere is also emigration and immigration into troupes which complicates it further. Please contact Dr Wolfgang Dittus who is having discussions with the Department of Wildlife on these control issues.
There are some points common to all animal populations. The basic means the carrying capacity of the system, so its not that the monkeys don't have enough to eat in the forest but the monkey population has grown due to the abundant resources found in human areas, crops, garbage and even people feeding them.
One is to control resources, such a garbage and people feeding monkeys.
Second it to impact a significant portion of the females in the population to prevent the population from growing. For dogs 70 - 80% of the females have to be sterilized within a 2 year period to see a significant drop in numbers and recruitment. (not hitting this 70% mark is the failing of the dog population control initiatives to date either by culling or sterilization).
There are many institutions in India working on controlling the Rhesus Macaque issue including birth control for females. I am not sure how cost effective or practical these things are.
But in general think about the whole problem in the bigger context of the monkey population and the area they inhabit. If one population gets weaker over time (due to interventions) another stronger group make take over the area. All these have to be thought of. Either way, a holistic approach in this regard unlike the ad hoc interventions for dogs which show little results.