Nineteenth-century naturalists split the grizzly into 86 species; genetics made it one
In the 1800s, naturalists carved grizzly bears into 86 separate species. By 1928 the count was seven, and by 1953 just one. Modern genetics goes further: the grizzly is simply North America's brown bear, the same species that roams Eurasia, just under a fiercer local name.
Lewis and Clark wrote the name as grisley, which might mean grizzled, for the grey-tipped fur, or grisly, for fear-inspiring. The modern spelling assumes the first, yet George Ord's 1815 scientific name, horribilis, plainly picked the second. Brown bears crossed from Eurasia into North America roughly 177,000 to 111,000 years ago, and most grizzlies still descend from that first wave. How many subspecies exist remains disputed; one DNA study found no clear groupings except the ABC Islands bears, which carry traces of polar bear ancestry.
Size depends heavily on diet. Coastal grizzlies on the salmon-rich Alaska Peninsula are giants, while bears in Canada's northern interior are barely bigger than local black bears. Telling the two species apart is a matter of shape: grizzlies have a muscular shoulder hump, a dished face, short rounded ears, a rump lower than the shoulders and front claws up to about 10 cm long.
Grizzlies once ranged from Alaska to Mexico and across the Great Plains; they now occupy about half that territory. Around 60,000 lived in North America in 2002, half of them in Alaska, where Admiralty Island packs roughly one bear per square mile. The lower 48 states hold far fewer, mainly around Montana's Northern Continental Divide and Greater Yellowstone. The California grizzly on the state flag is extinct, the last ones killed in the early 1920s; Arizona's last was shot in 1936, an event Aldo Leopold recorded.
Winter is survived by fasting. Grizzlies sleep in dens for five to seven months, neither eating nor relieving themselves, and females give birth during this time to cubs that can weigh under half a kilogram. Males surface in March, mothers a month or two later. Slow breeding is why recovery in former haunts will take a long time.
Source: Grizzly bear
