Human-monkey interaction in Sri Lanka: mitigation through attitudinal change

Human-monkey interactions have reached crisis proportions in Sri Lanka over the last 10 years due to extensive deforestation.  Amidst complaints from the public to find an immediate solution to the problem, Cabral et al. try to look at the negative interaction as a whole to develop a strategic plan to minimize negative interactions and promote harmonious coexistence through attitudinal change in people.

The biological significance of the trouble-makers

Extensive deforestation in Sri Lanka over the past 10 years has led to an increase in human-monkey interactions.  Since monkeys are involved in many types of conflicts, cause financial loss, and instill fear — both psychological and of health hazards, human attitudes towards them can be expected to be extremely intolerant.  Since the three species of monkeys recognized to be involved in interactions with humans — the Purple-faced Langur Semnopithecus vetulus, the Tufted Grey Langur S. priam thersites, and Toque Macaque Macaca sinica — are endangered and endemic to Sri Lanka, people’s attitudes towards them is of utmost significance for their long-term conservation.  This study reviewed the letters of complaints from the public to authorities concerned to extract information on human-monkey interactions and people’s attitudes towards the problem.

Understanding the interaction as a whole

Damage to crops and property were the most frequent categories of conflict.  The most number of complaints were reported from the densely populated Colombo District and were mainly against the Critically Endangered Purple-faced Langur subspecies S. v. nestor, which has an extremely fragmented and sparse distribution.  Toque Macaque was responsible for complaints from the highest number of people and districts — probably because of its wider distribution in the island.  This forest-dwelling omnivore has readily adapted to eating food discarded with garbage in urban areas and tourist sites.  M. s. opisthomelas, the Toque Macaque highland subspecies with a very restricted distribution in montane habitats, was considered a pest in some areas.

Minimizing negative interactions and promoting peaceful co-existence

As monkeys fed by people typically display aggressive behaviour, strict regulations need to be enforced against feeding animals; this, however, may be extremely difficult to implement in Sri Lanka where animals are given food to gain merit.  Proper waste management systems should be implemented to prevent monkeys from having access to garbage.  Guarding crops and installing barriers to prevent monkeys from entering houses may be successful in minimizing damage caused by the animals.

Translocation of problem animals is only a temporary solution — neighbouring monkey groups will quickly take over the vacated home range and the conflict will recur.  Preventive strategies to control monkey population require a huge financial investment and are difficult to implement on large populations.  If the capture of problem monkeys is essential, it must be carried out under strict guidelines by the authorities concerned on scientific and conservation bases, and the captured animals should be relocated into shelters after sterilising all individuals.  A series of field surveys have been initiated to identify community conservation areas, sites suitable for long-term protection of monkeys and other wildlife and managed by local stakeholders on a sustainable basis under the supervision of authorities concerned.

Reference

Cabral, S.J., T. Prasad, T.P. Deeyagoda, S.N. Weerakkody, A. Nadarajah & R. Rudran (2018). Investigating Sri Lanka’s human-monkey conflict and developing a strategy to mitigate the problem. Journal of Threatened Taxa 10(3): 11391–11398; https://doi.org/10.11609/jott.3657.10.3.11391-11398