A Possible answer to the emerging monkey menace in Kandy

Abstract

Toque Macaques (Macaca sinica) are found through out the Kandy District. Their daily invasion from the surrounding jungles into human habitats has posed a threat to the day- to-day activities of people because of their destructive and aggressive behaviour. This report suggests a possible solution to this ''monkey menace" by controlling their population via surgical sterilization, and then releasing them back to the jungles as a new and independent troop. Five males and two females used in this study were captured during a period of one year in Kandy using either mosquito nets, trapping cages or tranquilizing with Xylazine HCI 2% and Ketamine HCI 5%. One to two days after capturing, the males were subjected to pre- scrotal castration and the females to ovario-hysterectomy after sedation and anaesthesia with Xylazine HCI (10-14 mg) and Ketamine HCI (50-100 mg). Absorbable suture material (Polydioxanone monofilament or braided Polyglycolic Acid) was used on all monkeys. Long-acting penicillin and Tetanus toxoid were injected to all and they were observed for 10 days in individual cages. Complications due to scratching and rubbing against the cage were seen only in one female where 2 skin suture dehisions were treated as open wounds successfully. A new troop was not released due to the possible attack by the wild troops. The new troop was kept in a special cage comprising 8 interconnectable compartments and a common corridor made of iron bars and 2"x 2" iron mesh. Establishment of the troop was done in 7 phases. First, the behaviour of individual monkeys in separate cages was observed. Observations were then made after 2 monkeys were released to the corridor; followed by grouping them into couples, triplets, quartets, and finally after all were put together. After the troop was established, they were monitored for 5 observation hours per day for 5 consecutive days using a scan sampling method. These data were compared with those of a similar study done earlier on captive and free ranging Toque monkeys, in order to observe whether the new group is a socially acceptable troop. Variables such as foraging, locomotion, sitting/resting, self and social grooming, playing, fighting and mounting were compared using chi-square test at 5 % statistical significance. The troop was only different in fighting and sitting/resting when compared with the captive torque monkeys in zoological gardens in a previous study. The reason for this difference may be the sizes of the cages. Interestingly three out of eight variables examined namely, mounting, social grooming and playing were similar with those of the wild troop in the previous study(p < 0.05). The study group has established itself in to an independent troop and they are in semi captive state. They could be released to a natural habitat and monitored.