Sri Lanka experimenting with IUDs to tackle monkey menace 

Sri Lankan scientist tests IUDs on macaques to control population, amid government's shotgun distribution to farmers.

In a bid to address Sri Lanka’s “monkey menace”, a Sri Lankan academic is testing out intrauterine devices (IUDs) on female macaques, to possibly control the population of the specie commonly found in the island nation.

While there is no official number, scientists estimate there are roughly 3 million toque macaques in the country. Last year, the Sri Lankan government resumed issuing shotguns to farmers, amid mounting complaints of serious damage to crops by wild animals. The government’s move came after it scrapped an earlier proposal to export monkeys to China that was widely criticised by conservationists.

The ongoing experiment seeks to adapt intrauterine devices (IUDs), an increasingly popular long-term contraception method for humans — upon insertion into the woman’s uterus, an IUD prevents pregnancy — to the monkey species. Use of the device on animals is only at an experimental stage, according to Prof. Ashoka Dangolla, a senior veterinary scientist attached to the University of Peradeniya, in Sri Lanka’s central Kandy district, who is leading the experiment.

“We fit the IUDs in eight monkeys about three months ago and are monitoring their response. The next stage will require introducing sexually mature male monkeys. If the male and female monkeys mate with them, we would be able to study if the female monkeys get pregnant. The third stage would be a field trial,” he told The Hindu.

Prof. Dangolla has been involved in various community initiatives to tackle the monkey population for some 15 years now. “It takes many years for [birth control] surgeries in male monkeys to begin impacting the population,” he said. For his ongoing experiment, he used regular IUDs sourced from India, after resizing them locally for use on the monkeys. “To complete the experiment, I would need more support,” he said, adding that there is currently little government backing for his experiment. 

Meanwhile, experts remain sceptical of birth control measures on animals, that have been tried in other contexts. Wolfgang Dittus, a renowned primatologist based in Sri Lanka, who has been studying the island’s toque macaques for over half a century contended that contraception takes many years to affect population reduction, and that it is neither desirable nor practical to capture and treat all monkeys.

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