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
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.
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 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.
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.
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.
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."
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.
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.
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.
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.