Black bears (Ursus americanus)
The black bear or American black bear, which is found in both the US and Canada, is the only bear species that is uniquely endemic to North America. Despite its name, and although principally black, there are many different colour phases of black bear, ranging from jet black to white. These two colour extremes are evident in the sub-species Ursus americanus kermodii, the Kermode or " spirit" bear, which is found in some areas of the west coast of British Columbia.
The brown phase of the black bear, better known as the cinnamon black bear, is probably the most commonly seen and recognised variant. Cinnamon black bears vary from dark chocolate brown to light gold, and some colourations make them difficult to distinguish from grizzly bears, where their ranges intersect. Another less known variant of the black bear is the "blue" black bear or "glacier" bear, which is endemic to the Tatshenshini area of north west British Columbia.
Unlike grizzly bears, black bears are widespread in most of the US and Canada outside the Arctic, though the northern limit of their range depends on the treeline. Black bears exist in the same ecosystems as grizzly bears, though they occupy different niches within it, the black bear being a resident of the montane zone, the grizzly bear one of the alpine zone. Grizzly bears and black bears have a non-interactive tolerance in terms of sharing the same ecosystem, which breaks down on occasions, generally to the detriment of the black bear. Where the two species coincide, black bears significantly outnumber grizzlies, generally by a ratio of 10:1. Black bears exist throughout the contiguous United States, and can adapt better than grizzly bears to disturbance by human beings. As a result, black bears can survive in relatively close proximity to people and human infrastructure in a way that grizzly bears cannot. In this sense the black bear can be compared, in the bear family, to the coyote in the dog family ? coyotes are also found throughout the United States and are able to adapt to human settlement and disturbance. The wolf, however, like the grizzly bear, requires very large areas of wild land if it is to thrive, and it does not do so where there is a high human presence. Inevitably, wolves will leave disturbed areas, and their present range within the United States, running through the northern states, from Washington to Maine, is a reflection of this. An interesting correlation in this is the fact that human beings are generally less afraid of black bears and coyotes than they are of grizzly bears and wolves, which also results in our being more tolerant of them. This is significant, but the different behaviours and requirements of the specific species has more relevance in the situation.
The description of the life-cycle of the black bear is very similar to that of the grizzly bear, while the main differences between the two species are mostly to do with appearance and, again, more related to behaviour than biology.
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The peak of the black bear mating season is roughly from June to mid-July. Implantation of fertilised eggs in the uterus, however, is delayed until Autumn, and embryonic development only occurs in the last 10 weeks of pregnancy, which lasts about 220 days. Cubs are born in the den between January and March, with litters being generally larger than those of grizzly bears, often comprising three and sometimes four young. Cubs average ? to ? lb at birth, and are generally weaned at around 6-8 months. Like brown bears, Cubs stay with their mother for their first two years but will remain with her longer if she does not conceive at that time. Female black bears reach sexual maturity at 4-5 years old, while males mature about a year later.
Weights of black bears vary significantly according to region, and to availability and quality of food in a particular locale. An adult male can weigh up to 700 pounds, and yet an average weight in a general area where such a bear may be found might be 200-250 pounds. It is difficult to state an overall average weight for any age or sex class of black bear due to how widespread the species is, but in terms of region, bears in the southern rocky mountain area are generally smaller than in the northern Rockies. Similarly, in the southern states, unless influenced by a particular abundance or quality of food, bears are generally smaller than in northern New England or in Eastern Canada. As is the case with many wildlife species, human numbers, in relation to habitat quality, and depredation pressure, may have had the result of reducing the overall size and weight of black bears. In North America, northern habitats are generally less disturbed and less populated by people than southern ones; northern bears may therefore benefit from more natural and plentiful food sources. In addition, the colder climate may be conducive to larger or heavier animals through demand for more fat deposition for the hibernation period.
Cinnamon black bear, Yellowstone National Park, USA
The black colour phase is a very obvious distinguishing feature of black bears, but in any of the brown, or cinnamon, phases, other, more reliable features that can be used to identify a black bear are as follows: Black bears have no shoulder hump, and they have a straight, or "roman" nose, which actually falls in a very subtle convex arc from top to bottom. Black bears also have relatively larger ears than grizzlies, and they have the appearance of sticking up higher on the head. Black bears have curved claws, which allow them to climb trees. There are also a number of behavioural traits that distinguish black bears from grizzlies: Black bears are generally less aggressive than grizzly bears, and there is a good deal of evidence to show that they are normally less aggressive in response to a challenge or threat. For example, a person has a good chance of repelling a black bear, in the event of an encounter, if they make a directly aggressive display, whereas a grizzly bear, in the same situation, would be more likely to attack.
Cinnamon black bear, Waterton Lakes, Alberta, Canada
Black bears are predominantly herbivorous, though, like all bears, they are omnivores and opportunists ? if they find meat, they will eat it, though the majority of what they do find will be carrion. An interesting exception to this is the spirit bear, a large part of whose diet is comprised of fish. Like grizzly and polar bears, black bears are capable of great speed, being able to reach 30mph in a short dash. However, although extremely potent, the black bear is seldom associated with the phenomenal strength or potential aggression of the grizzly bear, traits that placed the latter in a very particular place in the human psyche. In the wild, a black bear has the potential to live for 30 years, but the average life span is probably much lower due to the extreme likelihood of conflict, of one form or another, with human beings. Whether this comes about because of hunting in any particular season, traffic, or encounter with people, very few black bears, like grizzlies, reach anything like their potential longevity.