brand logo

Crop-raiding monkeys least of the problems: Dr. Dangolla

25 Aug 2020

  • No census on wildlife available yet
  • Change in behaviour and feeding patterns closely monitored
  • Leopard urine the best deterrent
By Sarah Hannan Former President Maithripala Sirisena’s statement that farmers are confronted with a serious problem due to crop-destroying monkeys during the debate on the Government’s policy Statement has turned the spotlight on the primate population in Sri Lanka. Sirisena claimed that the monkey population in Sri Lanka had become twofold since the time he was in office as the Minister of Agriculture in 2005. “While no census has been conducted to definitely know the change in any type of species population at present, we are continuously studying the behaviour pattern changes of not only monkeys, but other crop raiding species too and have mapped that there are 11 species attracted towards the rural and urban cultivation zones. More than the monkeys, the peacocks are noted to be the biggest destroyers of crops as they tend to pick out the seeds and the plants that are planted by farmers,” University of Peradeniya senior lecturer of the Department of Veterinary Clinical Sciences Dr. Ashoka Dangolla noted. Dr. Dangolla noted that their behaviours have now evolved, where they are drawn towards the more populated areas such as villages and towns as they are gradually adapting to finding their feeds from home gardens and fields. “We are experimenting deterrent methods to keep these animals away from raiding crops. Leopard urine is the most effective deterrent, especially to keep away monkeys. We also dressed dogs in leopard print kits, which also seems to work as monkeys are afraid of leopards,” he elaborated. In addition to that, reflective surfaces (discs, metal strips, stripped cans, and empty toothpaste tube turned inside out), equipment that makes loud noises, and scarecrows too seem to work up to some extent, he said. He noted that while the population of monkeys have not grown, we are just seeing the diminishing tribes of monkeys a little too often as they are now driven out of their natural habitats – the forest – as their dwellings are felled and they are running out of food sources in the forest areas. As of August 2020, the International Union for Conservation of Nature (IUCN) Red List of Threatened Species lists the toque macaque – commonly known as rilawa or purple-faced leaf monkey – under its endangered species category. Wildlife and Nature Protection Society (WNPS) member and former Department of Wildlife Conservation Director General Dr. Sumith Pilapitiya noted: “The purple-faced leaf monkey might go extinct by 2050 due to severe habitat loss caused by rapid urbanisation in the western region of Sri Lanka. It is also listed as one of the 25 five most endangered primates in the world.” He said that these primates are adapting to feed themselves from the village rather than the forest as they are losing their habitat and their food due to rapid deforestation and urbanisation. Studies show that although farmers believe that primates cause more damage to their crops than other animals, the actual damage caused by primates is far less than what the farmers believe it to be (Riley, 2007; Siex and Struhsaker, 1999). The large body size and group size of the primates magnify the actual extent of damage caused (Nahallage and Huffman, 2008). Therefore, it is necessary to systematically quantify the damage caused by primates and communicate these findings to farmers. The toque macaques and langur species are not distributed equally throughout Sri Lanka (Nahallage and Huffman, 2008), and as a result, the damage caused by them differs according to the location. For example, in places where all three species can be found (Matale and Nuwara Eliya Districts in the Central Province, and Badulla and Monaragala Districts in the Uva Province), toque macaques are considered the most serious crop raiders. Also, in the Central and North Western Provinces, where the toque macaque numbers are said to be larger, they are considered as more serious pests than langurs. Purple-faced langurs are the most prominent species found in the Western Province and some parts of the Southern Province (Galle District). They cause more crop damage and are considered greater pests in these areas than toque macaques. In some parts of the Southern (Hambantota District) and North Central Provinces, grey langurs cause greater crop damage than the purple-faced langur or toque macaque.


More News..