Understanding Sloth Bears — An Interview With Dr. K. Yoganand

CI: Tell us about your research on sloth bears

I conducted intensive field research on sloth bears (Melursus ursinus) between 1996 and 2000 in Panna National Park (Madhya Pradesh), a partly degraded, dry deciduous forest habitat in Madhya Pradesh, central India. I captured and fitted radio-collars on several sloth bears and followed them to observe their behaviour and learn more about their secretive lives, such as, when did they sleep, what did they eat, how far did they move in a night, where did they give birth, where did they get all the food they needed, what did they do when they met a tiger, what circumstances prompted them to attack humans…

I also assessed the quality of the forest from a sloth bear’s point of view – how much area of the forest was covered by woodland, grassland and other types of habitats; how many different kinds of trees and shrubs were there that produced fruits eaten by sloth bears; how many fruits were produced by a single tree in a year; how many ant nests could be found in a hectare of forest, etc. I put all this information together to form a picture of a typical day in the life of the sloth bears of Panna.

Dry deciduous forests probably hold a major proportion (about 50%) of the sloth bear population in India. Unfortunately, degradation of habitat by humans has been severe in this forest type. For informed conservation planning and management of this habitat and the sloth bears that inhabit it, it was essential to have baseline information on their behaviour and ecology. Further, we felt that conducting a study in a human impacted area would help in objectively assessing how various human-induced impacts affect bear behaviour. From 2002 to 2008 I also periodically conducted additional field research in other sites, including a preliminary assessment of the distribution and status of the sloth bear across India.

CI: What methods did you employ to capture and collar sloth bears? Any interesting encounters?

I used barrel/culvert traps, which is a type of cage trap, and foothold cable snares to capture sloth bears for fitting radio-collars for my research.

One day I had a real surprise in store when a tigress got caught in one of the traps set for bears – something that I did not expect or want. The traps were not meant to withstand the weight or force of tigers. Anyway, I did not want to waste an opportunity. So I approached the big cat on one of the Forest Department’s camp elephants and got close enough to shoot a tranquilizer dart and immobilize it. I then fitted a radio-collar on it, which proved useful for my research on interactions between sloth bears and tigers, and for a colleague’s tiger research in Panna.

CI: A lot of your research involved following sloth bears on foot. Given their ferocious reputation, how risky was this?

It was quite risky! They are powerful animals and are known to sometimes attack and injure people even without any provocation. This is an integral part of their survival tactic in the jungle where they have to live alongside powerful predators such as the tiger. My tracking on foot was mostly limited to daylight hours except on some occasions when it became absolutely necessary to track at night. In general, my field assistant and I were very watchful. We kept our distance and were confident of reacting quickly if the situation became tricky. We had some close and tense encounters but were never injured by the bears.

CI: Describe a typical sloth bear attack on a human.

Most sloth bear attacks can be classified as ‘defensive’ attacks. When a human intrudes into its space suddenly, a bear may sense a danger to its life and respond by attacking.
In Panna NP, attacks typically happened when the bears were resting during the day or foraging in the early evening period in dense shrub-covered areas (degraded Lantana covered areas). When people traveling through forests or tending cattle inadvertently went too close, the panicked bears attacked in self-defense.

CI: How should one behave in case of a sloth bear attack?

The first thing one needs to do is to avoid getting into a situation where one may encounter a bear suddenly, such as avoiding dense shrub-covered localities, particularly in the evening and morning times when bears are likely to be active. And to avoid being alone in such places at such times. In the event of an attack, if one is not able to move away or chase the bear away, it has generally been advised to protect the face, head, neck, and nape by lying on the ground face down and covering the nape with locked hands. It should be noted that sloth bears do not feed on humans, and at the most they will bite and claw. If no further provocation occurs they may retreat after the initial attack. It should also be noted here that there is no strict rule about the way a bear may attack or a failsafe guideline about how humans should react during such encounters. The behaviour of a bear may be shaped by its past encounters with humans – in short, there may be personality differences in the way bears attack or retreat in such encounters.

CI: What are some of your key research findings?

Life History: Although my study was not long enough to gather information on all life history aspects, I was able to make many observations, which I combine here with what is known from other studies.

• In Panna, cubs were born in secure dens where the mother bears secluded themselves for several weeks to nurse and protect the newborns. Cubs stayed with their mother for up to two-and-half years and even rode piggyback for several months while she moved about foraging.
• After learning seasonal food finding and other survival skills from their mothers, cubs set out on their own. Males probably disperse into new areas while females set up their home ranges near their natal home ranges. The independent young adults/sub-adults carry out their normal activities of finding food, water, shelter and mates through the year within an area generally known as home range.
• Females may first breed at the age of three or four and give birth to one or two young ones every second or third year until the age of about 15 years. Adult males seek out breeding females every year and mate with them. Many males may mate with a female, according to a pecking order established among the adult males. Who actually sired the offspring will be unknown to the males and that perhaps ensures the protection of cubs from possible killing by adult males. Male longevity in the wild is probably up to 12-15 years; females may live a few years longer.

Home range: sloth bear home ranges range in size from a few square kilometers to more than a hundred square kilometers; male ranges are much bigger than those of females. In habitats with abundant food resources, home range sizes are likely to be small and vice versa.

Social behavior: sloth bears live mostly solitary lives, except for mother-young associations. Sometimes, siblings that have become newly independent of a mother may stay together for some time. During the breeding season male bears may stay with females for some days. They are not territorial and their home ranges overlap to a considerable extent.

CI: What is unique about the sloth bear?

The sloth bear is an ant and termite eating (myrmecophagus) bear. It is the only bear species that seems to depend almost entirely on these social insects for its protein requirements and thus, in this respect, it is unique among bears.