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Collared!
The Sri Lankan sloth bear is a “rarely-seen enigma”. Dr. Shyamala Ratnayeke and her team radio-collared ten of them to study this vulnerable sub-species.
By Ruwanthi de Silva
In the dense jungles of Wasgamuwa, Dr. Shyamala Ratnayeke and her team have been on the trail of the ten sloth bears of Sri Lanka, the first to be radio-collared in this country. The Sri Lankan sloth bear (melursus ursinus inornatus) is one of the most elusive and lesser-known animals of the planet.

Wasgamuwa has around 100 bears, says Dr. Ratnayeke, an assistant professor at the University of Tennessee, who has been on the trail of the sloth bear for the past two years in a project endorsed by the Department of Wildlife Conservation and the Ministry of Environment and Natural Resources. The project is supported by grants from the University of Tennessee.

"The objective of the study is to learn more about this rarely-seen enigma of the Sri Lankan jungles and identify key biological requirements affecting its survival and distribution to develop a sound conservation plan," says Dr. Ratnayeke.

The bear family (ursinus) comprises eight species, most of which are found in the Northern Hemisphere. The sloth bear (M. ursinus) is found in India, Bangladesh, Nepal and Bhutan but the Sri Lankan Sloth Bear is a sub-species endemic to Sri Lanka. Evidence suggests this bear maybe ecologically and behaviourally unique.
Radio telemetry, a powerful research tool for studying animal species that are shy, nocturnal and secretive was used by Dr. Ratnayeke in her study, as it allows the collection of ecological and behavioural data of known animals, without having to visually observe them.

Radio telemetry involves trapping a bear and then putting a collar on it so it can be studied for a period of two to three years. The collar is manufactured in a way that it will fall off within that period. A barrel trap is baited with bees' honey and placed in areas where bears roam. When the bear is in the trap, it is sedated and the collar is put on. Once it is weighed and its physical attributes noted, it is set free. "The bears usually leave a scat when they leave the trap, as though to say, ‘Hey! I have been here!’,” Dr. Ratnayeke adds with a laugh.

Ravana and Sita are the first radio-collared bears. The others include Manika, Kalu, Elara, Nelun, Dutugamunu who is the biggest male weighing 200 pounds, Lakshmi the biggest female, Parakrama and Michael named after Dr. Ratnayeke's advisor.

Dr. Ratnayeke and her three field workers walk in on the bears occasionally to monitor their progress. Recalling one encounter Dr. Ratnayeke said, "We lay on our bellies observing Michael reclining in a nice shady daybed, slapping at flies and wriggling around making himself comfortable. When we tried to retreat quietly, he sprang up, breaking twigs and branches and barking in our direction. We stood our ground and Michael crashed off in the other direction while the four of us crouched frozen, hearts in our mouths."

The progress of the animal is then measured through radio trekking. Radio telemetry provides information on survival and causes of death. This has enabled Dr. Ratnayake and her team to find out how sloth bears use their habitat, how much space they require, how they are active and how far they move.

On bear behavioural patterns she says, "Bears are primarily nocturnal, but it’s not unusual to see them moving about during the day, especially during the Wira season." Even though sloth bears belong to the order of carnivora (a group of mammals with a predatory or flesh eating ancestry) sloth bears don't hunt and are largely insect eaters, their favourite being termites! "Termites form a dietary staple. Bears have large protrusible lips, nostrils that can seal shut, and powerful claws for digging, which are especially adapted for eating termites," she added.

The sloth bear's physical features include coarse, shaggy black fur and a characteristic whitish horseshoe-shaped mark on the chest which makes it easy to recognize it. The sloth bear is the only bear to have long hairs on its ears. Dr. Ratnayeke's research has revealed that bears are not territorial, but that male bears do fight over females.

The reproductive rate of bears is very slow and most females will have only one cub and occasionally two. "The reproductive interval between births is more than three years and the gestation period is about 6 -7 months. Due to delayed fertilization the cub is born small and underdeveloped. The female bears stay in their dens for up to two months when the cubs are born and do not feed during this period. The cubs ride on the mothers’ backs when they are small, and stay with them for up to 916 days which is longer than any other bear species," Dr. Ratnayeke explained.

Though the sloth bear is listed as a vulnerable species by the Inter Union for Conservation of Natural Resources (IUCN), Sri Lankans are largely unaware of the need to protect them. “I suspect there is a lot of poaching by hunters. One of my radio collared bears was killed. The hunters shoot out of fear as sloth bears are not friendly and due to their poor eyesight and hearing, confrontation may have devastating consequences,” she says adding that walas thel is also marketed as an ayurvedic treatment for hair loss.

Their sheer power, mobility and predatory ability command fear and respect but increasing de-forestation and human disturbance in both protected and unprotected areas will surely see the decline of the sloth bear, warns Dr. Ratnayeke.

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