American black bear
Description
Seasonal variation in weight is very pronounced: in autumn, their pre-den weight tends to be 30% higher than in spring, when black bears emerge from their dens. American black bears on the East Coast tend to be heavier on average than those on the West Coast, although American black bears follow Bergmann's rule and bears from the Northwest are often slightly heavier than the bears from the Southeast. Adult males typically weigh between 57–250 kg (126–551 lb), while females weigh 33% less at 41–170 kg (90–375 lb). In the state of California, studies have indicated that the average mass is 86 kg (190 lb) in adult males and 58 kg (128 lb) in adult females. Adult American black bears in Yukon Flats National Wildlife Refuge in east-central Alaska were found to average 87.3 kg (192 lb) in males and 63.4 kg (140 lb) in females, whereas on Kuiu Island in southeast Alaska (where nutritious salmon are readily available) adult American black bears averaged an estimated 115 kg (254 lb). In Great Smoky Mountains National Park, adult males averaged 112 kg (247 lb) and adult females averaged 47 kg (104 lb) per one study. In one of the largest studies on regional body mass, bears in British Columbia averaged 73.7 kg (162 lb) in 89 females and 103.1 kg (227 lb) in 243 males. In Yellowstone National Park, a population study found that adult males averaged 119 kg (262 lb) and adult females averaged 67 kg (148 lb). Black bears in north-central Minnesota averaged 69.9 kg (154 lb) in 163 females and 124.95 kg (275 lb) in 77 males. In New York, the two sexes reportedly average 135 kg (298 lb) and 74 kg (163 lb), respectively. It was found in Nevada and Lake Tahoe region that black bears closer to urban regions were significantly heavier than their arid-country dwelling counterparts, with males near urban areas averaging 138 kg (304 lb) against wild-land males which averaged 115.5 kg (255 lb) whereas peri-urban females averaged 97.9 kg (216 lb) against the average of 65.2 kg (144 lb) in wild-land ones. In Waterton Lakes National Park, Alberta adults reportedly averaged 125 to 128 kg (276 to 282 lb). Adults typically range from 120 to 200 cm (47 to 79 in) in head-and-body length, and 70 to 105 cm (28 to 41 in) in shoulder height. The typically small tail is 7.7–17.7 cm (3.0–7.0 in) long. Although they are the smallest bear species in North America, large males exceed the size of other bear species, except the brown bear and the polar bear.
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