FAQ: Sloth Bears
by Shyamala Ratnayeke
Page 1
: Morphology, Range and Diet
What is a sloth bear?
Sloth bears belong to the mammalian order
Carnivora, and the family Ursidae (the bears).
A sloth bear (Melursus ursinus) is not the same as a
sloth, which is a slow-moving mammal in the order
Edentata, found in central and South America. Most
adult male sloth bears weigh between 80-145 kg, and adult
females weigh between 55 and 95 kg. Sloth bears have a
typically black shaggy coat, which is especially long around
the ears and neck. Most sloth bears have a white chest blaze
that looks something like a V-neck sweater, and a whitish
muzzle.
Sloth Bear Facts and Figures
| Latin name |
Melursus ursinus |
| Appearance |
Sloth bears have black
shaggy coats, though some are closer to cinnamon or red. The
underbelly fur is very sparse. All have a very obvious
light-colored chest patch, usually in the shape of a
"U" or "Y."
The lips, teeth, and nose are well-adapted for
termite feeding
|
| Size |
Adults are 60 to 75 inches
long, with males weighing between 175 and 310 pounds and
females between 120 and 210 pounds |
| Habitat
preferences |
Sloth bears prefer
low-elevation forests and grasslands |
| Range |
Sloth bears are found
mostly in India and Sri Lanka, but have also been reported
in Bangladesh, Nepal, and Bhutan |
| Reproduction |
Mating occurs throughout
May, June and July. Cubs appear six to seven months later,
with one or two cubs in most litters. They stay with their
mothers until reaching adulthood at about two years of age |
| Social system |
Very little is known about
sloth bears, though it is generally thought that they are
solitary and control small homeranges. Like giant pandas,
they have a vocal vocabulary that is not understood |
| Diet |
Termites makes up the
majority of a sloth bear's diet, though they also eat eggs,
carrion and vegetation. Sloth bears in Nepal have been known
to eat fruits |
| Status |
Listed in CITES Appendix
I. They face severe habitat loss and poaching, as well as
losses to natural predators like wild dogs, tigers, and
leopards.
The IUCN recognizes the sloth bear as one of the
species most threatened by extinction
|
| Captive status |
A Species Survival Plan
was initiated in 1994. The captive program is declining both
genetically and demographically |
Where are sloth bears found?
Sloth bears are found only on the Indian subcontinent
(India, Nepal, Bhutan, and possibly Bangladesh) and Sri
Lanka. Throughout their range, they are generally restricted
to low elevation forests and the low hill country (under
1000m). Melursus ursinus inornatus, one of two
recognized subspecies of the sloth bear, is endemic to Sri
Lanka and is possibly Sri Lanka’s most endangered
carnivore. Anecdotal evidence suggests that M. u.
inornatus may be morphologically and ecologically unique
but, until now, this subspecies has not received intensive
ecological study and its current status and distribution
remains largely speculative.
What do sloth bears eat?
Sloth bears eat a lot of termites, although they
also eat other animals (ants, grubs, eggs) and vegetable
matter. Fruit is often a large component of the diet, and
shoots and flowers of some plants are eaten. All sloth bear
studies in Nepal, India and Sri Lanka demonstrate this, but
it is important to recognize too that there will be seasonal
differences from one site to the next in how much of a
certain type of food is eaten. For example, wetter weather
generally means more termites are eaten, as it is easier for
the sloth bears to to dig for them. If a certain fruit is in
season, they may eat that almost exclusively for a few
weeks.
| | | Media Gallery |
Sloth Bear, Photographed by Remote Camera
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Not just another pretty face...
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Page 2
: Status and Reproduction
Why are sloth bear populations threatened?
The sloth bear is listed as "vulnerable" by the International Union for the Conservation of Nature (IUCN), although this listing depends on estimates of abundance, distribution and probability of extinction. These types of data on population status are limited for most of its range. There is general consensus, however, that existing sloth bear populations are becoming increasingly fragmented and are disappearing from many areas of their former range. Most sloth bear populations outside protected areas are very likely to have disappeared.
Both behavioral and life history characteristics of sloth bears place them at risk throughout most of their range, particularly where human densities are high and forests rapidly disappearing. This is especially so for India, Nepal and Sri Lanka, where both protected and unprotected areas in India and Sri Lanka experience heavy poaching and encroachment. Being large, aggressive carnivores, sloth bears require large areas of relatively undisturbed habitat for maintaining viable populations. In many parts of their range, sloth bears seem intolerant of human disturbance and may be absent or occur at very low densities in areas with high levels of human disturbance. Moreover, as with most large carnivores, the nocturnal and elusive nature of the sloth bear make assessments of its population status difficult.
In terms of their life history, ursids tend to have small litter sizes and extended periods of offspring dependence. Sloth bears tend to have smaller than average litter sizes for ursids. Moreover, sloth bear cubs may remain with their mothers for up to two years, and females may take as long as three or more years between births. These characteristics make for slow population growth rates, and consequently slow recovery if a population undergoes a bottleneck for some reason.
What do we know about the life and reproduction of sloth bears?
Observations from the wild and captivity indicate that sloth bears breed during June and July. There is period of delayed implantation, cubs usually being born between November and January. There is a possibility that there is no marked seasonality of breeding and births in the southern part of the sloth bear’s range—for example, in Sri Lanka—but data are scarce. Gestation may be between four and seven months and, similar to bears in temperate regions with highly seasonal environments, includes a period of delayed implantation, a short gestation, followed by the birth of small, altricial cubs. Some weeks prior to birth, pregnant females will enter a den and remain there, apparently fasting, for approximately two months. It is unusual that this pattern, which is typical of bears in temperate regions who undergo a lengthy period of winter denning and fasting, persists in a tropical bear in a relatively aseasonal environment.
Much of what we know of the life and reproduction of sloth bears in the wild comes from a capture and radio telemetry study conducted in Nepal in the early 1990s. Some years later, India launched a similar study. Pregnant females may dig their own dens in the ground, or use natural hollows . After nine to ten weeks of confinement, females will emerge periodically to feed and cubs will accompany her about one or two weeks later, usually riding on their mother’s back. Sloth bear cubs tend to ride on their mother’s backs almost continuously while traveling for their first few months. As they get older, they will periodically descend to feed and play, but tend to ride routinely on her back until they are about nine months old. This behavior is unusual for ursids and is considered a form of defense against large predators, such as tigers and leopards, that share habitat with sloth bears. It may also function as a safety measure from attacks by other adult sloth bears.
| | | Media Gallery |
Female Sloth Bear Carrying Cub
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Sloth Bear, Wasgomuwa NP
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Sloth Bear, Yala NP
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Page 3
: References
Garshelis, D. L., A. R. Joshi, J. L. D. Smith, and C. D. Rice. 1999a. Sloth Bear Conservation Action Plan (Melursus ursinus). Pages 225–240 in C. Servheen, S. Herrero, and B. Peyton, compilers. Bears. Status survey and conservation action plan. IUCN/SSC Bear and Polar Bear Specialist Groups, IUCN-The World Conservation Union, Gland, Switzerland.
Garshelis, D. L., A. R. Joshi, and J. L. D. Smith. 1999b. Estimating density and relative abundance of sloth bears. Ursus 11:87–98.
Joshi, A. R., D. L. Garshelis, and L. D. Smith. 1995. Home ranges of sloth bears in Nepal: Implications for conservation. Journal of Wildlife Management 59:204–213.
Joshi, A. R., D. L. Garshelis, and L. D. Smith. 1995. Sociobiology of the myrmecophagous sloth bear in Nepal. Canadian Journal of Zoology 77:1690–1704.
Phillips, W. W. A. 1984. The Sloth Bear. Pages 290-296 in Wildlife and Nature Protection Society of Sri Lanka, editors. Manual of mammals of Sri Lanka. Colombo.
Rajpurohit K. S. and P. R. Krausman. 2000. Human-sloth bear conflicts in Madhya Pradesh, India. Wildlife Society Bulletin 28(2):393-399.
Santiapillai, A., and C. Santiapillai. 1990. Status, distribution and conservation of the sloth bear (Melursus ursinus) in Sri Lanka. Tiger Paper 1:13–15.
Servheen, C. 1990. The status and conservation of the bears of the world. International Conference on Bear Research and Management Monograph 2.
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 About the author:
Dr. Shyamala Ratnayeke is studying sloth bears and other
carnivores in two Sri Lankan national parks.
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