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Asiatic Black Bears
(Ursus thibetanus)
The Asiatic black bear's scientific name, Ursus thibetanus, literally means "moon bear of Tibet". This bear is also commonly called the Tibetan black bear, the Himilayan black bear or the white-breasted bear due to its colouration.
Paleontologists believe that Asiatic black bears and American black bears may have shared a common ancestor as recently as 3 to 4 million years ago.
The Asiatic black bear lives in the moist broad-leafed forests which occur across much of southern Asia (see map). This area includes the countries of Pakistan, Afghanistan, eastward into northern India, China and finally across southeast Asia. Separate populations are also known to be present in eastern Russia, Korea, Taiwan and Japan. In parts of their range, they share the habitat with brown bears.
At present, there is no firm estimate of how many Asiatic black bears are still alive in the wild. While it is obvious that there are still a significant number of these bears still present, it is also clear that their future is extremely clouded and in doubt. Throughout most of their range, conservation efforts on behalf of the Asiatic black bear are almost nonexistent and where there is supposedly legal protection, it is rarely enforced.
The Asiatic black bear is a large mammal whose size and weight show high variability depending on food availability, climatic conditions, etc.
In general, adult Asiatic black bears have an average length between 140 and 165 centimeters (4 1/2 and 5 1/2 feet long).
The weight of a Asiatic black bear, which is highly variable, normally ranges from 90 to 115 kilograms (200 to 255 pounds). A very large adult male Asiatic black bear may weigh over 180 kilograms (400 pounds) prior to hibernation when it has its full fat resources. Males are generally larger than females within a specific geographic area.
The lifespan of Asiatic black bears in the wild can be twenty-five years or more.
Asiatic black bears have a heavy, stocky body comparable in size to the American black bear. Their ears are large and set far apart on their large, round heads. They walk in a plantigrade manner similar to other bears (i.e., both heel and toe make contact with the ground when walking in a manner similar to humans).
Their short claws, about 4 to 5 centimeters (1 to 2 inches) in length, are highly adapted to tree climbing and all Asiatic black bears are agile tree climbers.
The Asiatic black bear has a very dense black fur coat. A very pronounced thick mane, often as long as 15 centimeters (6 inches), also surrounds the head. In the area of the chest, the bear has a crescent moon-shaped patch of cream-coloured or yellowish-white markings. As well, the Asiatic black bear has cream-coloured or white fur along its lower lip and chin.
The Asiatic black bear still remains an active carnivore even though it has now adapted so that it eats both meat and plant material.
Asiatic black bears, like most wild creatures, seek foods which will return the highest nutritional value for the least expenditure of energy. Primarily a nocturnal animal, these bears will readily kill other mammals both large and small. They are hated by farmers for the killing of local livestock. Where other mammals are not available to the bear, such as in Japan, they are able to subsist on a more plant-based diet.
Seasonal availability and geographic location are the biggest factors determining the supplementary food sources of the bears. Eating virtually anything edible, their diet also consists of termites, beetles, larvae, honey, fruits, nuts and berries.
The size of the home range of an individual Asiatic black bear will vary with the concentration of high energy food sources. Thus, the more concentrated the food sources, the smaller the range necessary to maintain an animal.
While information on the specific territorial habits of these bears is just coming to light, it is initially presumed that it will be similar in nature to that of the American black bear.
Very little information is currently known about the reproductive behaviour of Asiatic black bears in the wild. From observing zoo animals, we surmise that normally breeding takes place over a one to two day period in late April to early June. Reports indicate, however, that mating has been observed as early as March and as late as December. Copulation normally takes place in a manner similar to members of the canine (dog) family.
The female usually enters a rock cavity or hollow tree during winter or early spring. Normally, she gives birth to two tiny cubs weighing approximately 223 grams (8 ounces). Again, climate and food supply are important determinants of the size of the litter.
Given the long period between mating and birthing combined with the small size of the cubs, it is strongly suspected that delayed implantation of some kind occurs with Asiatic black bears as it does for a number of other bear species.
Through this process, referred to as delayed implantation, the fertilized ovum divides a few times and then floats free within the uterus for several months with its development arrested. Several weeks before the mother enters the maternity den, the embryo will attach itself to the uterine wall and the cubs will be born while the mother is in the maternity den.
Within the next several weeks, the cubs will develop rapidly on the rich milk provided by the mother. They will then be able to follow her when she leaves the den to forage.
The survival of the cubs is extremely tenuous with predation by other animals probably quite common. In certain parts of their range, they coexist with brown bears who are known to kill other animals including other bears, particularly cubs.
The survival of the bear cubs is totally dependent on the skill of the mother in both protecting them and teaching them the basics of what to eat, where and how to get it, how to cope with danger and all the other skills of living in the wild.
The cubs will normally stay with the mother for the entire first year to year and a half. Normally they are driven off by their mother as she prepares to breed once more.
In the northern parts of their range, Asiatic black bears hibernate as do all bears from the northern hemisphere. Normally, they will enter their dens in November and leave them in late March or early April. Prior to denning, the bears have, as a survival imperative, the need to gain as much weight as possible in order to survive hibernation.
For these Asiatic black bears, the arrival of colder weather and/or snow precipitates them undergoing a remarkable metabolic transformation as they prepare for hibernation. Hibernation is an energy-saving process bears have developed to allow them to survive long periods when there is insufficient food available to maintain their body mass. As they stop eating and become increasingly lethargic, the bears will enter a cave; dig out a den; or hole up in a dense brush pile, hollow log or tree cavity.
While hibernating, a bear's heart rate drops from between forty to seventy beats per minute to only eight to twelve beats per minute and its metabolism slows down by half. Unlike many other animals who hibernate, its body temperature only undergoes a minor reduction of 3 to 7 degrees centigrade (5 to 9 degrees Fahrenheit).
During the entire period of hibernation, the Asiatic black bear will neither pass urea or solid fecal waste. While urea poisoning causing death would occur in all other animals, bears have developed a unique process of recycling the urea into usable proteins.
During the hibernation period, all bears lose a great deal of weight. Adult males and adolescent bears lose between 15% and 30% of their weight while it is not uncommon for a female cub with newborn cubs to have lost as much as 40% of her weight.
The Asiatic black bear will then resume its normal foraging pattern as it completes the cycle of life.
Asiatic black bears living in more southern parts of their range may sleep only for short periods or simply descend from higher elevations to warmer valleys where they are able to continue feeding uninterrupted.
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