CONTENTS

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

Ursus americanus - American black bear (Click photographs/illustrations for full picture & further details)

INDEX - INFORMATION AVAILABLE

Alternative Names (Synonyms)

• [Genus] altifrontalis, [Genus] amblyceps, [Genus] californiensis, [Genus] carlottae, [Genus] cinnamomum, [Genus] emmonsii, [Genus] eremicus, [Genus] floridanus, [Genus] glacilis, [Genus] hamiltoni, [Genus] hunteri, [Genus] hylodromus, [Genus] kenaiensis, [Genus] kermodei, [Genus] luteolus, [Genus] machetes, [Genus] perniger, [Genus] pugnax, [Genus] randi, [Genus] sornborgeri, [Genus] vancouveri. (B141). Black bear (B285.w4)

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 American black bear is a large carnivore with a heavy, blocky build, a straight or slightly convex facial profile, small eyes, round erect ears, a short tail, and short, tightly curved non-retractile claws on plantigrade feet. It has short hair, uniform in colour; black with a tan muzzle is typical in some areas but in other areas various shades of brown are more common. (B144, B180, B288.w11, D245, D248.w9)

Newborn:

• Newborn cubs have short greyish fur but are blind (closed eyes) and toothless. (B147, B180)

Similar Species

• Distinguished from Ursus arctos - Brown bear by its generally smaller size, a more uniform pelage colouration, usually darker fur, straight rather than dished facial profile, lack of a muscular hump on the shoulders, shorter hind feet, shorter claws on the forefeet (the claws on the forefeet being strongly curved and only slightly longer than those on the hind feet) and the three pairs of upper incisors being equal in size (in Ursus arctos the outer pair is much larger than the two inner pairs). (B147, B180.w2, B180.w3, B285.w4, D245)
• Very similar to Ursus thibetanus - Asiatic black bear, but not sympatric. (D245)
  • In captivity, may be distinguished by its larger body size, the lack of longer hairs fringing the cheeks and down the sides of the neck, and the lack of the characteristic creamy "V" or crescent on the chest from the sternum to the axillae. (B288.w11) [and see descriptions of Ursus thibetanus - Asiatic black bear]

Sexual Dimorphism

• Typically, males are 10% longer than females. (D245)

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
• 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
  • Hand-rearing American Black Bears
  • Release of Hand-reared American Black Bears
• Reproductive Management of Mammals
• Management of Unwanted or Illegally Held Animals

Measurement & Weight

EDITORIAL SUMMARY

LENGTH
Adult: Black bears measure about 1.2 - 1.9 m, with males typically larger than females, averaging 1.57 and 1.43 m respectively.
Newborns: Newborn cubs measure about 199 mm.

HEIGHT 
Adults and sub-adults: Black bears are about 0.7 - 1.05 m at the shoulder (2.3 - 3.4 ft).
Juveniles: --

WEIGHT
Adult: Male black bears may weigh 60 - 225 kg usually, but reach or pass 300 kg in some areas where they feed on corn. Females may weigh 40 - 150 kg usually but can exceed 180 kg.
Newborns: Cubs weigh about 250 - 360 g.

GROWTH RATE: The growth rate of cubs is affected by their mother's size and by food availability. One study found wild cubs to gain about 500 g in their first month and 2.5 kg in the first 12 weeks. Zoo data showed cubs to average 1.8 kg at a month old, 3.5 kg at two months and 10 kg at three months. Females reach full skeletal growth by four to five years, males by six or seven years. Weight gain continues for two or three years after skeletal growth has stopped. 

(References are available in detailed literature reports below)

Head and Neck

EDITORIAL SUMMARY

GENERAL HEAD STRUCTURE: 
Adult: The American black bear has a large head with small, rounded, erect ears, a straight or slightly convex facial profile, a tapering muzzle and long nostrils. The vibrissae are vestigial. The skull is massive with a large cranium, strong sagittal ridge and zygomatic arches, broad frontal region, well developed turbinates and flat, inconspicuous tympanic bullae.
Newborn: --

DENTITION:
Adult: Bears have unspecialised incisors, sturdy canine teeth and broad, flat molars. The black bear's dental formula is i3/3, c1/1, p4/4, m2/3 for a total of 42 teeth.
Neonate/Young: The deciduous dental formula is i3/3, c1/1 p3/3 (total 28 teeth).

EYES:
Adult: Black bears have relatively small eyes, with a well-developed nictitating membrane. The eyes are brown, but appear black at a distance.
Newborn: Cubs have blue eyes; these are closed at birth.

(References are available in detailed literature reports below)

Legs, Spine and Tracks

EDITORIAL SUMMARY

• Black bears have thick, relatively massive legs and short broad paws each with five toes and short, re-curved, non-retractable claws. The claws of the American black bear are shorter than those of Ursus arctos - Brown bear, being adapted to climbing rather than to digging. As with other bears, this bear is plantigrade.
• The forefoot print is about 100 mm (four inches) long by 125 mm (five inches) wide, with the hindfoot track about 180 - 230 mm (7 - 9 ins) long by 125 mm (5 ins.) wide. The hind print is placed several inches in front of the forefoot track on the same side. The stride is about 300 m (1 ft). The smallest toe does not always leave a visible mark; the claws may leave marks in soft ground.

(References are available in detailed literature reports below)

Tail

EDITORIAL SUMMARY

• The American black bear's tail is short, about 120 mm (4.8 inches) long, and may be hidden in the fur.

(References are available in detailed literature reports below)

Skin / Coat / Pelage

EDITORIAL SUMMARY

Adult: Black bears have a uniform coat but this varies in colour between individuals. In eastern North America, the commonest colour is black with a tan muzzle, while this is less common in southwestern populations. Other common colour phases are chocolate brown, cinnamon (reddish brown), beige and blond. Blue, blue-grey and white (not albino) individuals are also seen and the "silver" black bear has sides which are silvery grey with a blue lustre. The coat colour of a bear may change between successive moults and bears of different colours may be found in a given litter.

Adult Colour variations: Albinos occur rarely. Some individuals have a white mark on the chest.

Newborn/Juvenile: Cubs are born with short grey fur.

(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 and female reproductive organs, gastrointestinal system and urinary system. 

(References are available in detailed literature reports below)

Natural Diet

EDITORIAL SUMMARY

NATURAL DIET: 

• Black bears are omnivorous but primarily vegetarian. 
• In spring, emerging ground vegetation, catkins and leaf buds are important; hard mast left from the previous fall (autumn) will also be eaten if available, and carcasses may be eaten. In summer and fall, berries and nuts are important. 
• Animal foods eaten include insects such as ants, crickets and grasshoppers, fish, mammals, birds and reptiles.
• Black bears will also eat food in human garbage, agricultural crops such as maize (corn), oats, and apples, and honey from apiaries.

QUANTITY EATEN: About 5 - 6 kg (11 - 18 lb) of food is required daily. Tens of thousands of berries and nuts may be eaten daily.

STUDY METHODS: Foods eaten have been determined by analysis of scats, analysis of stomach contents and by observation of foraging bears.

(References are available in detailed literature reports below)

Hibernation / Aestivation

• American black bears hibernate for a period which varies with geographical location, from 5-7 months in the north (even eight months in Alaska) to 74-124 days in Louisiana, while further south only females producing cubs den. 
• Denning is probably stimulated by photoperiod with modification based on temperature and food availability. 
• Prior to hibernation they accumulate fat. During hibernation the bear does not eat or drink, neither does it urinate or defecate; 23-30% of total body mass is lost on average over the winter, with lactating females losing 45% more body mass than non-lactating individuals.
• Body temperature falls a few degrees and the respiratory rate decreases. In some areas bears may rouse easily if disturbed, but in others they rouse only slowly and after considerable prodding.
• Bears may rouse to gather more bedding if meltwater comes into the den, but do not awaken to forage in mid-winter even in warmer weather.
• In spring, males emerge earliest and females with cubs emerge latest.

(References are available in detailed literature reports below)

Haematology / Biochemistry

HAEMATOLOGY:

• The haematology values of bears are similar to those of domestic dogs. 
• Also see Reference Page:
  • Normal Haematology Values for Ursus americanus - American black bear 

BIOCHEMISTRY:

• The biochemistry values of bears are similar to those of domestic dogs. 
• Also see Reference Page:
  • Normal Biochemistry Values for Ursus americanus - American black 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); in hibernating bears it falls to 31 - 34 °C.

RESPIRATORY SYSTEM (RESPIRATION): The normal respiratory rate of bears is 15 - 30 breaths per minute (the higher rates have been recorded in hot weather); it is slower during hibernation. Much faster respiration can be seen in bears resting in hot weather, e.g. 130 - 140 in cubs in summer.

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): Faeces (scats) are roughly cylindrical, sometimes coiled, usually dark brown, and may contain visible seeds, grasses, insect parts, animal hair, nut shells or root fibres; they may be black and liquid if bears are feeding on berries. Food passage time is short.

URINARY SYSTEM (URINE): Urine specific gravity has been measured as 1.025.

CHROMOSOMES: 2n = 74 Chromosomes.

MUSCULO-SKELETAL SYSTEM: --

SPECIAL SENSES AND VOCALISATIONS:

• The American black bear's eyesight is poorer than that of humans, but they do have colour vision and at close range they have detailed vision and feed partially by sight. Distance vision may not be sufficient to allow black bears to stalk distant prey.
• The sense of smell is excellent; they may smell carrion at a distance of more than a mile (1.6 km). Scent is the main method used by a female bear to recognise her offspring.
• These bears have quite good hearing.
• There are a variety of vocalisations, including a startled "woof", contented purrs of cubs, shrill howls or squalls of uncomfortable or frightened cubs and an "uh-uh" grunt by females calling her cubs to her.

(References are available in detailed literature reports below)

Feeding Behaviour

EDITORIAL SUMMARY

• These bears feed for as much as 12 hours a day. They may travel some distance looking for food. 
• They will turn over stones, logs and buffalo dung looking for insects, tear apart decayed stumps and logs to reach grubs and insects, dig up roots, excavate rodent burrows and anthills and break branches of fruit trees. They occasionally climb trees to reach food and rip open trees to reach honeycombs, and remove bark from conifers in spring to reach the sapwood. 
• When feeding on berries, bears preferentially choose those growing in clusters, feed partially by sight, and eat mainly the most obvious clusters. 
• They will opportunistically eat available foods such as carcasses and large numbers of crickets. 
• They may kill Alces alces - Moose cows and calves, and Odocoileus virginianus - White-tailed deer fawns, and in some areas livestock. In the Labrador tundra, they hunt caribou (Rangifer tarandus - Reindeer) and small mammals. They also catch fish.
• Black bears make use of garbage dumps and bait set by hunters.
• Food caching has been seen occasionally.

Further information on diet is provided in American black bear Ursus americanus - Natural Diet (Literature Reports)) 

(References are available in detailed literature reports below)

Parental Behaviour

EDITORIAL SUMMARY

• For nursing, the female may lie on her back or side, or sit on her haunches with the cub(s) in her lap.
• Females pick up cubs in their mouth, either by grasping the whole thorax and abdomen (for cubs under about 1 kg) or by grasping the nape of the neck (for larger cubs).
• On rare occasions, females adopt cubs from other litters. 
• A black bear may abandon her cubs if disturbed in her natal den or if the den is destroyed by logging or construction work; however, often she will return to her cubs if disturbed from the den. One instance is recorded of a disturbed mother carrying first one then the other cub about 2.25 miles, then leading them away.
• A female in poor body condition may abandon her cubs or may consume newborn cubs.
• Cubs are sometimes left in "refuge trees" by their mother while she forages.
• Females look after their cubs for about 16-17 months; the family breaks up in the spring and only very rarely reunite after the mating period.

Further information on reproduction is provided in American black bear Ursus americanus - Life Stages (Literature Reports)

(References are available in detailed literature reports below)

Social Behaviour / Territoriality / Predation / Learning

EDITORIAL SUMMARY

• The size of home ranges varies greatly with habitat, being large where food resources are less abundant. Depending on area, home ranges of adults may or may not overlap with those of other adults of the same sex. Ranges are larger in flatter regions, where bears need to move further to find all their requirements, than in mountainous regions where altitude provides variety. Outside the mating season, bears may travel more widely to use seasonal food resources, before returning to their usual denning area (which is often but not always within their breeding range) to den for the winter.
• Territoriality varies between different locations. In some areas home ranges overlap. In others, females occupy separate territories, which they defend from other females. Exclusive feeding areas are advantageous where food resources are not abundant. Where females are territorial, ranges of males may overlap with several females during the breeding season, and with one another. Where ranges overlap, a given area is generally used by only one individual at a time, with smaller bears avoiding larger bears. In areas where territories are held, outside the mating season, bears may range more widely to find food. Bears may congregate and tolerate one another at some clumped food resources such as large garbage dumps.
• Population densities vary greatly, from 0.9 bears per 100 km² to 1.3 bears per km².
• Yearlings which have split from their mother generally remain within her home range. In the following years, young females generally establish a range within part of that of their mother, or adjacent to it while young males disperse.
• Bears can be marked using eartags, also with tattoos; natural markings can be recorded. Radiocollars are used for following bears; colouring of collars can be used to aid individual identification. Transmitters have also been attached to ears, glued to hair, or implanted intra-abdominally. 
• Black bears are generally considered solitary, but at clumped food resources several bears may be present. Tolerance between bears may be reduced as the mating season approaches. Sometimes young adult and subadult bears may associate with one another at a concentrated, abundant food resource, with two bears travelling with one another for a few days and playing together. Communication involves sounds, gestures and postures, as well as scent. A bear threatens a conspecific by laying back the ears and making a series of huffs, chopping its jaws, stamping its feet and sometimes charging. Bear trees (which may be trees, telegraph poles, sign posts etc.) are repeatedly marked by bears, by rubbing, clawing and biting. Marking is carried out most often by adult males in the period while their testosterone levels are high, also by females within their own territories. Bear trees may give information to other bears about sex, reproductive status and even individual identity and mood. They are sited in openings or along the sides of openings (including roads), and the open side is marked.
• Black bears compete with Ursus arctos - Brown bear where their ranges overlap. Interactions with wolves depend on numbers: lone wolves flee from black bears, and may be killed by a bear, but a pack may attack and even kill the bear. Black bears generally avoid humans and encounters which do occur usually are non-aggressive; even if the bear threatens it rarely carries through on a charge. Black bears may be important seed dispersers for some plants.
• Not many species prey on black bears. Young or small bears may be killed by bobcats, brown bears, coyotes, wolves and black bears. There are rare reports of adult females killed by wolf packs or by adult male black bears, and of adult male black bears killed by Ursus arctos - Brown bear. 
• Black bears spend the winter hibernating in a den. Females with cubs continue to use the den initially after emerging in spring. Further information on dens is given in: American black bear Ursus americanus - Nests - Burrows - Shelters (Literature Reports)
• American black bears are able to learn and to remember from year to year, as indicated by bears returning to multiple, distant food resources, and by females reestablishing in spring the same territories which they held the previous year. They also are able to learn to exploit new food resources, such as campers' food, and garbage dumps.

(References are available in detailed literature reports below)

Sexual Behaviour

EDITORIAL SUMMARY

• American black bears are promiscuous: females may mate with more than one male and males with more than one female. 
• Males wander during the mating season, finding females by following their scent trails. A male may stay with an oestrous female for hours to a few days. 
• Males compete for females; generally the larger male chases off the smaller male; evenly-matched males may fight. 
• The female stands still to let the male mount from behind; the male clasps the female with his forelegs and gives a series of pelvic thrusts. Each copulation lasts just a few minutes.

(References are available in detailed literature reports below)

Activity Patterns, Self-grooming and Navigation

EDITORIAL SUMMARY

ACTIVITY PATTERNS: Black bears have a clumsy, awkward-looking walk, swim well and climb very well. Even very young cubs climb, although not well until they are about 1.8 kg. Trees are climbed for protection from predators and to reach food. The annual rhythm of activity is arousal from hibernation, a period of lethargy, increasing activity as the first spring foods become available, mating season, the main feeding season through summer and fall (autumn), then hibernation.

SELF-GROOMING: Little has been reported, but scratching with a hind foot, and licking of the paws, has been described.

CIRCADIAN RHYTHM: American black bears may be crepuscular or mainly diurnal in wilderness areas away from humans but more nocturnal in habitats where there is human activity during the daytime.

SPEED OF MOVEMENT: Black bears generally walk quite slowly; a female was recorded as moving at about 1.6 - 2.7 km/hour when travelling without foraging, and more slowly when foraging. She moved more slowly when accompanied by cubs than when alone. For short distances, these bears may run as fast as 50-56 km/hr (30 - 35 miles per hour).

NAVIGATION: American black bears can navigate to distant food sources and to return home, but the mechanisms used are not known.

(References are available in detailed literature reports below)

General Habitat Type

EDITORIAL SUMMARY

• Black bears are mainly found in forests, particularly mixed forests with a wide variety of tree and shrub species. 
• They use swampy areas in eastern North America, dry, hot shrubby forests in Mexico, mossy coniferous rainforests in coastal Alaska and even treeless tundra in Labrador.

(References are available in detailed literature reports below)

Nests / Burrows / Shelters

EDITORIAL SUMMARY

• Black bears may den in a hollow standing live or dead tree, under a fallen tree, in a rock cave, or in a burrow dug by the bear (often under roots or logs).
• In southern areas, they may den in a nest of leaves and grass on the ground. Even in some northern areas, they may build large nests out of conifer boughs.
• Black bears usually line the den with leaves, grass, lichen, rotten wood or ferns and may close the entrance with leaves or grass, which both camouflages the entrance and helps in heat retention.
• Dens are quite small, usually just large enough to contain the bear.
• In general, black bears choose a different den from year to year.
• The oxygen level inside the den may fall as low as 15.9% if snow crusts over the den surface; this does not affect the bear's survival.

(References are available in detailed literature reports below)

Distribution and Movement (Migration etc.)

EDITORIAL SUMMARY

• Black bears are native to North America. 
• They are found through most of Alaska, all Canadian provinces and territories except for Prince Edward Island, through much of the USA except for the central plains and arid southwest, and eight states in northern Mexico.

(References are available in detailed literature reports below)

A map of their range is provided in B442 - Bears. Status Survey and Conservation Action Plan - Chapter 8 [full text provided]

Species variation

EDITORIAL SUMMARY

• Different authorities suggest different numbers of subspecies, up to as many as 16 or 18. Two subspecies which are widely accepted are the Louisiana black bear Ursus americanus luteolus and the Florida black bear Ursus americanus floridanus. The Kermode bear Ursus americanus kermodei is well known for some individuals having a white coat.

(References are available in detailed literature reports below)

Conservation Status

EDITORIAL SUMMARY

WILD POPULATION - IMPORTANCE: Wild populations of the American black bear are increasing in most of their present range of Canada and in many parts of the USA. The population trend in Mexico is generally uncertain, but even there, many populations appear to be increasing.

GENERAL LEGISLATION: In Canada, these bears are designated as a big game species and furbearer in most provinces and territories. In the USA, 34 states classify black bears as game species, but six of these have no open hunting season; nine states classify black bears as protected, threatened or endangered, and in four states - Hawaii, Illinois, Indiana and Iowa - they have no legal designation. Under the US Endangered Species Act, the subspecies Ursus americanus luteolus (in Louisiana, eastern Texas, southern Mississippi) is listed as a threatened subspecies. In Mexico, they are legally classified as "endangered" by the Mexican wildlife agencies.

CITES LISTING: Appendix II under the "copycat clause" since body parts are indistinguishable from those of Asian bears. 

RED-DATA LIST STATUS: Lower risk / least concern.

THREATS: There are no major threats in Canada, but there is habitat loss in some areas. In the USA, there are threats from loss of and fragmentation of habitat, political restraints on management, poaching in some states, depredation kills in some states, road kill in a few states and over harvest in a few states. In Mexico, they are threatened by habitat loss due to overgrazing, land clearing and woodcutting, and by poaching.

PEST STATUS / PEST POPULATIONS: In Canada, black bears cause some problems with crop damage, livestock depredation, damage to apiaries and nuisance bears round garbage; they are considered as a pest in the agricultural areas of Manitoba. In the USA, many states find that black bears cause damage and nuisance in relation to garbage (27 states), apiaries (27 states), property (21 states), agricultural crops (14 states) or timber (12 states). In Mexico, the main reported problem is cattle predation.

CAPTIVE POPULATIONS: ISIS lists 320 American black bears in ISIS member institutions.

TRADE AND USE: Black bears are hunted legally in much of Canada and the USA.

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

(References are available in detailed literature reports below)