CONTENTS

Living Organisms / Animalia / Craniata / Mammalia / Carnivora / Ursidae / Melursus / Species

Melursus ursinus - Sloth bear (Click photographs/illustrations for full picture & further details)

INDEX - INFORMATION AVAILABLE

Alternative Names (Synonyms)

• [Genus] inornatus, [Genus] labiatus, [Genus] longirostris, [Genus] lybius, [Genus] niger. (B141).

The first time this bear was described it was named Bradypus ursinus - bear-like sloth; a few years later it was recognised as a bear and named Melursus lybius; later it was named Ursus labiatus. (B435.w1)

Names for new-borns / juveniles

Names for males

Names for females

General Appearance

"Bears have a big head; a large, heavily build body; short, powerful limbs; a short tail; and small eyes. The ears are small, rounded, and erect." (B147)

• Bears are strongly built, with a broad, longish head bearing short round ears and relatively small eyes. The lips are free from the gums, and protrusible; the molars are broad and nearly flat. They have a heavy body and a very short tail. They are plantigrade, with five toes, approximately equal in length, to each paw; the paws are wider than those of canids (Canidae - Dogs, foxes (Family)) and the curved, non-retractile claws are longer and stronger. (B144, B288, B424)
• The sloth bear is a medium-sized bear, with long, untidy-looking hair, black, often with a brownish tinge, or occasionally brown; on the breast is a whitish area, V-shaped or crescent, and the tips of the feet are yellowish or dirty white. The hind legs are short, the claws are hooked and ivory white, The muzzle is long and greyish, the lips are long (the lower lip can be stretched over the outer edge of the nose); the tongue is long and flat. (B144, B288.w11, B392.8.w8, a href="../../../../00Ref/BooksContents/b436.htm">B436.10.w10)

Newborn: Newborn cubs are barely furred, with closed eyes. (N22.30.w1)

Similar Species

• The sloth bear is distinguished from other bears by its heavy, shaggy fur and its rolling gait. (B288.w11)
• Distinguished from Ursus thibetanus - Asiatic black bear by its larger build, longer, shaggier coat and white claws. (B392.8.w8) The sloth bear also has a much whiter muzzle. Both have a ruff of fur around their neck. (V.w98)

Sexual Dimorphism

References

Species Authors & Referees

Referees: Ellen Dierenfeld (V.w16), David L. Garshelis (V.w98)

• See DIRECTORY- Organisations working with Bears

• Bears Status Survey and Conservation Action Plan - Chapter 12
• See also: The Electronic Library- further reading for "Bears- Health and Management"

Husbandry Information

Notes

• Bears are large, strong mammals, adapted to climbing trees and/or difficult terrain, and with claws adapted for climbing and/or digging. Their ability to climb and to claw open trees should be remembered in designing enclosures. 
• Bears are intelligent, curious and adaptable. They are predominantly diurnal, as seen in undisturbed habitats in the wild, and are mainly solitary. 
• The behavioural, social and psychological requirements of bears must be taken into consideration in enclosure design and husbandry.

Management Techniques

• Accommodation Design for Mammals
• Mammal Behavioural Requirements
• Food and Feeding for Mammals
• Mammal Handling & Movement
• Mammal Identification
• Preventative Medicine for Mammals
• Rearing of Mammals
• Reproductive Management of Mammals
• Management of Unwanted or Illegally Held Animals

Measurement & Weight

EDITORIAL SUMMARY

LENGTH
Adult:

• 1.4 - 1.9 m (5 - 6 ft)

Newborns: --

HEIGHT
Adults and sub-adults:

• 0.6 - 0.92 m (2 - 3 ft).

Juveniles: --

WEIGHT
Adult: Suggested weight range 55 - 145 kg (121 - 320 lb) or even rarely over 190 kg (419 lb).

• Males perhaps 80 - 145 kg (176 - 320 lb) (rarely over 190 kg/419 lb)
• Females about 55 - 95 kg (121 - 209 lb).

Newborns:

• 450 g.

GROWTH RATE

• Zoo data: Average weight at one month 2.5 kg, at two months 4.5 kg and at three months 6.8 kg. (D247.6.w6)

(References are available in detailed literature reports below)

Head and Neck

EDITORIAL SUMMARY

GENERAL HEAD STRUCTURE:
Adult: The sloth bear has a mobile snout and long, protrusible, mobile, hairless lips with no vibrissae. The nostrils can be closed off using a projection of the rhinarium. This is done by the bear pushing its nose against a surface such as the side of a hole in which it is digging; it is used to allow the bear to suck in ants or termites with its mouth. The tongue is also unusually protrusible. The palate is deeply concave. As with other bears, the ears are small.
Newborn: --

DENTITION:
Adult: Bears have unspecialised incisors, long sturdy canines and broad, flat molars. The adult dentition of sloth bears is i2/3, c1/1, p4/4, m2/3 x2 = 40, lacking the first (central) pair of upper incisors.

Juvenile: The deciduous dentition of sloth bears includes central upper incisors but these are small.

EYES:
Adult: As with other bears, sloth bears have small eyes. and a well-developed nictitating membrane.
Newborn: The eyes of cubs are closed at birth.

(References are available in detailed literature reports below)

Legs, Spine and Tracks

EDITORIAL SUMMARY

• Sloth bears have relatively short hind legs. The claws of the hind feet are only about 3 cm long but those of the front feet are longer (about 7 cm) and slightly curved, good for digging. The soles of the feet are naked and the digital pads are mainly fused together. The claws are whitish or greyish in colour.
• Bears have a caudal extension to the shoulder blade (scapula), called the post-scapular fossa, from which the subscapularis minor muscle arises; this is used in climbing, pulling the bear's body up.

(References are available in detailed literature reports below)

Tail

EDITORIAL SUMMARY

• The sloth bear has a short tail, only about 100 - 125 mm (4 - 5 ins) long.

(References are available in detailed literature reports below)

Skin / Coat / Pelage

EDITORIAL SUMMARY

Adult: The sloth bear's coat is usually black, sometimes brown tinged, usually with a white or buff "V" or "U" shaped chest mark. The muzzle is greyish, with short, thin, whitish hair. Over the body the hair is long and coarse, with no undercoat. From just behind the ears to the shoulders the coat is very long - up to 30 cm - but on the face (just below the eyes to the ears) it is short. The pale chest markings may serve to accentuate the threat display when the bear stands on its hind legs.

Adult Colour variations: Occasional individuals are brown, cinnamon or red rather than black. Some individuals lack the pale chest mark.

Newborn/Juvenile: The coat of cubs is black or rarely light-cinnamon.

(References are available in detailed literature reports below)

Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

EDITORIAL SUMMARY

• Bears do not have any major anatomical specialisations.

Further information is available within this section on the male reproductive organs, gastrointestinal system and urinary system. 

(References are available in detailed literature reports below)

Natural Diet

EDITORIAL SUMMARY

NATURAL DIET: The main foods are colony-living ground-dwelling ants and termites, and common sugar-rich fruits; flowers and honey are also eaten.

QUANTITY EATEN: Different studies have indicated termites to be most important in the diet (Chitwan, Nepal) or fruit and ants to be most important (Panna, India).

STUDY METHODS: The relative quantities of different foods eaten may be determined by analysis of scats (composition of scat remains). Preferably, data from this is converted to indicate consumed biomass of food items eaten. Other methods include observation of bears eating, and reports of crops eaten by bears.

(References are available in detailed literature reports below)

Hibernation / Aestivation

• This bear is not known to hibernate. However, parturient females remain in a birthing den, without eating, for about two months.

(References are available in detailed literature reports below)

Haematology / Biochemistry

HAEMATOLOGY:

• Haematology values of bears are similar to those of domestic dogs. 
• Also see Reference Page:
  • Normal Haematology Values for Melursus ursinus - Sloth bear 

BIOCHEMISTRY:

• Blood biochemistry values of bears are similar to those of domestic dogs. 
• Also see Reference Page:
  • Normal Biochemistry Values for Melursus ursinus - Sloth bear

(References are available in detailed literature reports below)

Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

EDITORIAL SUMMARY

METABOLISM (TEMPERATURE): The normal rectal temperature of adult bears is 37.5 - 38.3 °C (99.6 - 101.0 °F). 

RESPIRATORY SYSTEM (RESPIRATION): The normal respiratory rate of bears is 15 - 30 breaths per minute (the higher rates have been recorded in hot weather).

CIRCULATORY SYSTEM (PULSE/HEART RATE): The normal heart rate of bears is 60 - 90 beats per minute (the higher rates are found in cubs).

HAEMATOLOGY / BIOCHEMISTRY: Values are similar to those of the domestic dog.

GASTROINTESTINAL SYSTEM (FAECES AND GUT MOTILITY): --

URINARY SYSTEM (URINE): --

CHROMOSOMES: 2n = 74 Chromosomes.

MUSCULO-SKELETAL SYSTEM: --

SPECIAL SENSES AND VOCALISATIONS:

• These bears may have relatively poor sight and hearing but a good sense of smell. 
• Marking of trees by biting and clawing, rubbing and sometimes by defecating, may act as a form of olfactory communication. 
• They use a variety of vocalisations while feeding, during interactions with other bears (roars, howls, screams and squeals) and on encountering predators.

(References are available in detailed literature reports below)

Feeding Behaviour

EDITORIAL SUMMARY

• Sloth bears turn over rocks and logs to reach ants and termites, break open termite mounds with their claws, blow the debris away and suck out the termites, and may dig 1.5 m deep to reach large underground ant colonies. 
• They climb trees to reach honey bee nests and sometimes for fruit, but fruit is mainly eaten when it falls. 
• In hot weather these bears may have to dig in dry stream beds to reach water.

Further information on diet is provided in Sloth bear Melursus ursinus - Natural Diet (Literature Reports)) 

(References are available in detailed literature reports below)

Parental Behaviour

EDITORIAL SUMMARY

• The female sloth bear remains in a secure den with her cubs until they are six to ten weeks old. 
• Once they leave the nest, she often carries them on her back as a protection against predators. 
• The family stays together for 1.5 or 2.5 years.

Further information on reproduction is provided in Sloth bear Melursus ursinus - Life Stages (Literature Reports)

(References are available in detailed literature reports below)

Social Behaviour / Territoriality / Predation / Learning

EDITORIAL SUMMARY

• Sloth bears have relatively small home ranges; the size of the home range appears to vary depending on food resources present and may vary seasonally. A study in Royal Chitwan National Park, Nepal, found home ranges of males to be larger than those of females (14.4 km² and 9.4 km² respectively) and wet season ranges to be 1.9 times larger than dry season ranges. In Panna National Park, India, home ranges were 25 - 100 km² and also varied with season.
• Population densities were estimated at 25 - 72 bears per 100 km² in Royal Chitwan National Park, Nepal and 6-8 bears per 100 km² in Panna National Park, India, which is a low-productivity habitat.
• These bears are mainly solitary except for females with cubs. However, sometimes two subadults are found together, possibly for mutual protection. The bears may gather at abundant food resources.
• Cubs leave their mother at about 2.5 years of age.
• Sloth bears may be aggressive to humans and other large animals; they are likely to attack if disturbed and if they encounter humans unexpectedly.
• In captivity, hybridisation with Helarctos malayanus - Sun bear has been reported.
• Tigers may attack sloth bears; cubs may be predated also by leopard and by large canids (Canidae - Dogs, foxes (Family)).
• Nests or dens are used for thermoregulation, and by females for cubbing.

(References are available in detailed literature reports below)

Sexual Behaviour

EDITORIAL SUMMARY

• Males gather around a receptive female and all may mate her, apparently in order of rank.

(References are available in detailed literature reports below)

Activity Patterns, Self-grooming and Navigation

EDITORIAL SUMMARY

ACTIVITY PATTERNS: These bears shelter in shallow caves or dense vegetation in cool weather. In hot weather they may have to travel to find water.

SELF-GROOMING: Bears lick themselves as part of grooming.

CIRCADIAN RHYTHM: These bears are considered to be mainly nocturnal, but may be seen active at any time of the day. Nocturnal or crepuscular activity may be to avoid the heat of the day. In some areas, females with cubs, and subadults, are active more during the day; this may be to avoid other bears or predators.

SPEED OF MOVEMENT: Females carrying cubs move more slowly than do other adult bears.

NAVIGATION: --

(References are available in detailed literature reports below)

General Habitat Type

EDITORIAL SUMMARY

• Sloth bears are found in moist forests such as deciduous monsoon forests, and in dry forest such as thornbrush woodlands; they may also be found in grassland areas.

(References are available in detailed literature reports below)

Nests / Burrows / Shelters

EDITORIAL SUMMARY

• Sloth bears use a cave or den in hot weather and during the rains; in cooler weather they sleep in tall grass or in shade under trees.
• Females use a natural cave or dig out a den for cubbing.

(References are available in detailed literature reports below)

Distribution and Movement (Migration etc.)

EDITORIAL SUMMARY

• Sloth bears are found only on the Indian subcontinent: in India, Nepal, Bhutan, Sri Lanka and possibly Bangladesh.

(References are available in detailed literature reports below)

Maps of their range are provided in B442 - Bears. Status Survey and Conservation Action Plan - Chapter 12 [full text provided]

Species variation

EDITORIAL SUMMARY

• The sloth bears of Sri Lanka are smaller and are generally considered a separate subspecies, Melursus ursinus inornatus.

(References are available in detailed literature reports below)

Conservation Status

EDITORIAL SUMMARY

WILD POPULATION - IMPORTANCE:

• Sloth bears are vulnerable; their total population is probably less than 20,000.

GENERAL LEGISLATION: --

CITES LISTING: Appendix I.

RED-DATA LIST STATUS: Vulnerable. 

THREATS: The sloth bear is threatened by human disturbance and habitat loss, hunting (for body parts, also due to crop damage and because it is considered dangerous) and capture of cubs for use as "dancing bears" in India. Bears that attack or threaten to attack people may be destroyed.

PEST STATUS / PEST POPULATIONS: These bears sometimes damage crops, particularly where habitat degradation has reduced the availability of natural foods. They may attack humans when they are encountered unexpectedly, for example in fields at night. In parts of India, encounters between people and sloth bears have led to numerous human injuries and many deaths. Such incidents tend to occur where people frequently use bear habitat, and where the habitat has thus become severely degraded. 

CAPTIVE POPULATIONS: There are more than 70 sloth bears registered in zoos worldwide, but there are more in collections in India.

TRADE AND USE: In India, these bears are sometimes used as "dancing bears." Body parts are used as alleged medicines, for food and as decorations.

For more information see: B442: Bears. Status Survey and Conservation Action Plan - full text provided

(References are available in detailed literature reports below)