SLOTH BEARS: CHARACTERISTICS, BEHAVIOR AND REPRODUCTION

SLOTH BEARS

sloth bear

Sloth bears (Melursus ursinus) are small- to medium-size bears found in the lowland forests of India, Nepal, Sri Lanka and Bhutan. They were found in Bangladesh but are now considered extinct there. Able to thrive in a variety of habits, including thorn scrub, grasslands, wet rain forests,hills with shrubs trees and stones and dense forests, as long a sufficient food supply is available, these animals are unique among bear species in that they feed primarily on ants and termites like anteaters and females carry their young on their back. [Source: Adele Conover, Smithsonian; John Eliot, National Geographic, November 2004]

The first reports of sloth bears by European hunters in India described their trunk-like snouts, their habit of hanging from tree limbs like sloths in Latin America and their baby-like cries. John Eliot wrote in National Geographic, “ Scientific blunders can live on forever. When 18th-century European museum curators were first sent specimens of a large furry mammal with long curved white claws, they named it "bear-like sloth" because its claws resemble those of South American sloths. In the early 19th century, a sloth bear, housed in a zoo in France, was examined by scientists who identified it correctly as a bear species and after that the name was changed from "bear sloth" to "sloth bear".

Two subspecies of sloth bear have been identified: 1) the Indian sloth bear (Melursus ursinus ursinus); and 2) the Sri Lankan sloth bear(Melursus ursinus inornatus). The the Indian sloth bear is found throughout India, in the Terai of Nepal and parts of Bhutan. This species was fairly common in India as recently as 20 years ago, but is now harder to find. The Sri Lankan sloth bear is smaller. Not so long ago it occurred throughout Sri Lanka. But due to wide-scale conversion of upland forests into tea and coffee plantations, it is now restricted to the northern and eastern lowlands. [Source: Wikipedia]

It is estimated that between 10,000 and 25,000 sloth bears remain, primarily in enclaves scattered across India, where between 6,000 and 11,000 of them live. On the International Union for Conservation of Nature (IUCN) Red List they are listed as Vulnerable. In CITES (Convention on International Trade in Endangered Species of Wild) they are in Appendix I, which lists species that are the most endangered among CITES-listed animals and plants. Sloth bear numbers have been reduced by poaching and habitat loss. In the old days they were hunted out of many areas. In some part of India cubs have been abducted for the dancing bear trade. Sloth bears occupy many of the same areas as tigers and conservation efforts to help tigers have also helped sloth bears.

Websites and Resources on Animals: Bear Conservation bearconservation.org ; Bear Book and Curriculum Guide web.archive.org ; Animal Diversity Web animaldiversity.org ; BBC Earth bbcearth.com; A-Z-Animals.com a-z-animals.com; Live Science Animals livescience.com; Animal Info animalinfo.org ; World Wildlife Fund (WWF) worldwildlife.org the world’s largest independent conservation body; National Geographic National Geographic ; Endangered Animals (IUCN Red List of Threatened Species) iucnredlist.org

Sloth Bear Characteristics

sloth bear range (green - extant, black - former)

Sloth bears are 1.4 to 1.8 meter (4½ to 6 feet) long, with a 7 to 13 centimeter (2.7 to 5.1 inch) tail, and range in weight from 55 to 140 kilograms (121 to 308 pounds). Adults stand 60 to 90 centimeters (two to three feet) at the shoulder. Their average basal metabolic rate is 47.064 watts. Their average lifespan in captivity is 30.0 years. Some have lived over 40 years. Sexual Dimorphism (differences between males and females) is present: Males are 30 to 40 percent heavier than females Males weigh 79– 141 kilograms (175–310 pounds); females weigh 54–95 kilograms (120 — 210 pounds). [Source: LeeAnn Bies, Animal Diversity Web (ADW) /=]

Looking like big balls of unkept fur, sloth bears have stocky bodies and short, powerful limbs allowing them to gallop as fast as a human can run. The animals’ course fur gives them a slovenly appearance but it also helps protect them from stinging insect bites and cold spells. The fur is thickest on the back of the neck, and particularly shappy around the shoulder, making the bear look like it has a mane. The fur is relatively sparse on its belly and underlegs, perhaps to keep the animal cool in hot weather. They don’t seem to be too bothered by the heat and often are seen sleeping in the day, exposed to the hot tropical sun.

Sloth bears have large feet and long, non-retractile foreclaws and a white, brownish or yellowish V on their upper chests that varies from a U shape to a Y or O. In the old days hunters used the white mark as target when they shot at the bears. Brown and grey hairs found on the coat give the appearance of a cinnamon color on some bears. They are the only bear with long hair on the ears.

Sloth bears have a long muzzle which is similar to but less elongated than that of anteaters. The molars are broad and flat, representing their trending away from being carnivorous. Compared to their body, their face appears naked and grey. They have extremely large tongues, a mobile snout, and they can voluntarily open and close their nostrils, all of which are useful when they shove their snout into the dirt in the quest for ants and termites. prove helpful with their diets. These bears have a light "U" or "Y" shaped patch on their chests.

Sloth Bear Behavior

sloth bear mother with cubs

Sloth bears are generally solitary and nocturnal but can be observed at any time of the day. The only time males and females come together is to mate (often in June and July). Generally, the only groups are a mother with cubs but brief groups of five to seven bears have been observed, communicating with strange facial expressions and a variety of sounds. Sloth bears spend much of their ambling along in a slow, deliberate fashion, looking for food. If motivated they can gallop at a relatively high speed. Sloth bears generally don’t hibernate but retreat to caves and have a period of relative inactivity during the rainy season.

Sloth bears sense using touch and chemicals usually detected with smell. Their sense of smell is well developed and they have high sensory perception but their sight and hearing are poor. These bears are generally not aggressive, but their poor eyesight and hearing allows humans to draw near, and when feeling threatened these bears can defend themselves with nasty result. During the day they often sleep in caves by river banks. [Source: LeeAnn Bies, Animal Diversity Web (ADW)]

Sloth bears can not be accused of slothfulness. They are quite busy. They spend almost all their free time searching for food. They generally don’t defend territories; they just roam to where the food is. Their long claws are ideal for digging and fending off attacks not so good for climbing trees, which many other bears their size are good at. They produce a variety of sounds, including roars, squeals, howls, huffs, yelps, rattles and gurgles. They are particularly noisy when mating, when they also engage in mack fighting and hugging. When resting they make humming and buzzing noises sucking on their paws.

Sloth Bear Aggression and Intelligance

Sloth bears are known for their pugnacity and aggressiveness They can do some serious damage with their long claws. They sometimes bite with their semi-toothed muzzle and hold on like a pit bull. Females are generally accommodating to other females. Fights sometimes break out between males.

Sloth bears have been observed fighting with tigers and holding their own. One ranger told Smithsonian magazine he observed a sloth bear slap a tiger in the face and push it away. The tiger fled after that. The same ranger said the once saw a sloth bear take on three large tigers, each of which fled in a different direction after the encounter. However, tigers do kill sloth bears more often than visa versa. In most cases a tiger can kill a sloth bear of it wants to but is fearful if suffering severe wounds in the process.

In May 2006, sloth bears at the Beekse Bergen Safari Park in the Netherland treed a Barbary Macaque and then ate it in front of horrified zoo-goers. A zoo statement confirmed the incident. "In an area where Sloth bears, great apes and Barbary macaques have coexisted peacefully for a long time, the harmony was temporarily disturbed.” Apparently several Sloth bears chased the Barbary macaque into an electric fence, where it was stunned. It then fled onto a wooden structure, where one bear pursued and mauled it to death. Other bears then consumed the simian. [Source: Yahoo! News, May 15, 2006]

Sloth bears are regarded as very intelligent, employing reasoning when they feed. Sometimes before a rainstorm they dig a number of small holes in a termite nest and allow the rain to make them bigger before they dig up the hole. Like other bears, sloth bears can stand up on their hind legs, It first though this was a sign of aggression but it turns out they seem to do it to get a better view or survey the landscape and. more importantly, to sniff the air for food or danger.

Sloth Bear Feeding

Sloth bears are omnivores (eat a variety of things, including plants and animals). Half their diet is termites, ants and beetle larvae. Termites are an especially abundant and reliable food source in the tropics. They also feed on fruits, leaves, roots, tubers, honey, eggs and flowers. Occasionally they will eat the remains of a tiger kill. They sometimes raid maize, sugar cane and yam fields and compete with villagers to collect sweet Mohwa flowers. Sloth bears compete with wild cats, canids (dog-like animals) and pigs for ants and termites.

Sloth bears sound like bellows when using their flexible snouts and lips to blow away dirt and suck up termites and ants. They like mangoes and figs. Fifty percent of their diet is fruits during March to June, and termites and other insects the rest of the time. One study found that sloth bear prefers habitats rich in fruit trees, such as Ficus glomerata and Diospyros melanoxylon (rich sweet fruits), and the presence of honey, ants, and termites. When near populated areas sloth bears may feed on cultivated crops like sugar cane and maize /=\

Sloth bears have a long, extremely flexible snout, nostrils that close, almost prehensile lips and no incisors on their upper jaw. These adaptions allow they suck up large amount of ants and termites. They retain their lower canines, presumably for fighting. John Eliot wrote in National Geographic, “The front end of a sloth bear is unmistakable. From its shaggy black head protrudes a long whitish muzzle. The three-inch-long front claws are ivory white. These are the tools of this specialized bear's trade: feeding on termites and ants by ripping up their mounds and nests. “

Sloth bears feed by tearing open termite and ant mounds in soil, old logs or trees with their foreclaws and pushing their long, flexible snouts into hole and blowing away the dirt around termites. When it eats it closes its nostrils and purses its lips and sucks insects like a vacuum cleaner through a gap in formed by missing upper incisor teeth and a hollowed out upper palate. This sucking action is also accompanied with a series of puffings and belchings which can be heard up to 200 meters away. Their ability to voluntarily open and close their nostrils prevents the inhalation of dust during this process. The bears leave behind a hole wide and deep enough for a man to stand in up to his chest. Termites are a very secure food source, as they are present all year round. It is estimated that a sloth bears eats between 4,000 and 10,000 ants or termites at one time (between a pint and quart).

Sloth bears have been observed in the spring feeding on honeycombs hand from tree branches, A 1977 article in Journal of Zoology read: “Uisng the claws as hooks, the bears can climb large diameter trunks. They descend by sliding backwards, sometimes making use of hanging creepers. On one occasion a bear was seen straddling a horizontal branch using a forepaw to scoop up honeycomb from below the brancg and periodically wiping the bees from his face.” Although the beers cry out when stung the continue at it until the whole honeycomb is consumed.

Sloth Bear Mating and Reproduction

According to Animal Diversity Web: Information on the reproductive behavior of sloth bears varies. Some studies have them mating mostly between May and July, whereas others report mating and giving birth at any tiime of year. These differences may be due to the location of the bears studied. Field studies in India found sloth bears to mate mostly in June. On the other hand, field studies in Sri Lanka discovered they mate over a greater part of the year.[Source: LeeAnn Bies, Animal Diversity Web (ADW) /=]

Sloth bears tend to be very noisy during mating In captivity, a pair only mates for about one to two days. Most births occur from September to January. Pregnancy lasts between six and seven months. One to two offspring are usually born, rarely three, but it does occur. Females usually search for a cave or a ground shelter in which to give birth

On average females and males reach sexual or reproductive maturity at three years of age. The average gestation period is six to seven months. Birthing usually takes place in a ground shelter of some sort. The gestation period for sloth bears us around six or seven months. Because they usually give birth in December or early January it is thought the experience delayed implantation (a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months).

Sloth Bears and Their Young

Sloth bears are altricial. This means that young are born relatively underdeveloped and are unable to feed or care for themselves or move independently for a period of time after birth. Cubs are blind for about three weeks after birth. Following a period of about four to five weeks the young leave the den. Pre-weaning stage provisioning and protecting are done by females. Pre-independence protection is provided by females. Ccubs stay with their mother until they reach adulthood at about two to three years of age. [Source: LeeAnn Bies, Animal Diversity Web (ADW) /=]

Sloth bears give birth to their young in a den, often cave, natural hollow or hole dug by the bear under a large rock. Typically a female gives birth to two cubs in November to January. The cubs are born helpless and hairless and the mother stays with them for 35 days before emerging from the den. The cubs stay in the den for two to three months. After that the mother sloth carries her cubs “bearback” until they are about six months old, when they may as much as third of their mother’s weight. The cubs become independent when they are around two.

Sloth bears are the only species of bear that carry their young on their back. Their long course fur is easy to grip. Mothers carry their young like this perhaps as a precaution against tigers, leopards and other predators, allowing her to hold off potential attackers while her young are safe behind her. The cubs cling to their mother’s back even when she is digging a termite nest or charging a tiger. They rarely change their position, with one cub riding near the neck and the other near the rumps and always maintaining those positions. When alarmed the cub bury themselves in their mother’s fur.

At about three months, the cubs start to briefly come off their mother; back to play and snoop around. With the slightest threat they leap back on their mother’s back. Cubs will remain with their mother for three years, a year longer than other bear species, before heading out on their own. During their time together, the mother gives the cubs essential training. Orphans don’t know which part of a termite mound to dig and can climb trees fine but get stuck and don’t know how to get down.

Sloth Bear Versus Tiger in India

In April 2024, visitors at Pilibhit Tiger Reserve in India witnessed and videoed a rare confrontation between a sloth bear and a tiger. Live Science reported: The scene unfolded at the protected area in India's northern Uttar Pradesh state. Visitors on a safari filmed the encounter and posted a video to the social platform X. The video shows a tigress sauntering down a dirt road and then stopping in her tracks when a sloth bear from the trees ahead. [Source: Sascha Pare, Live Science, June 8, 2024]

The bear wanders across the road and disappears behind long grass as the tigress watches. Moments later, as the tigress strolls on, the bear reappears and chases after her. "A rarest of rare sight of a bear charging toward a tigress, captured today at Pilibhit Tiger Reserve," Rajiv Kumar Gupta, a retired government official with the Indian Administration Service who witnessed the encounter, wrote in the post.

In the video, the tigress whips around when she hears the bear charging after her, but she does not attack and instead stands her ground. After a few seconds of the two predators facing off, the bear retreats back into the trees.

"Apex predators usually have a mutual respect for each other especially if they are of a similar size," Tara Pirie, a lecturer in ecology and conservation at the University of Surrey in the U.K. who was not on the safari at the time of the encounter, told Live Science in an email. "The tiger took time to watch the bear, sizing it up possibly to understand more about it. The bear did not show a particularly aggressive charge from the video so the tiger must have decided it was big enough to stand its ground." Predators of similar strength and size tend to avoid unnecessary fights, as fighting wastes energy and puts both parties at risk of injury, Pirie said.

In this case, the tigress may have been particularly reluctant to engage in a struggle because she was nursing three young cubs at the time of the encounter and could not "afford any injury," said Jitender Govindani, a professor and member of the academic council at ICBM School of Business Excellence in Hyderabad, India, who witnessed the standoff. Govindani noted the tigress appeared to surrender when the bear charged.

"The tigress lowered her guard and surrendered when the bear got into attack mode," Govindani told Live Science in an email. "Once the tigress surrendered the bear left immediately, as [it] was also not keen to fight and showed aggression just [to] show its readiness to take on the tigress head on if provoked to a fight."

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, BBC, CNN, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated January 2025