All About Grizzlies
Learn about grizzlies: their habitat, behaviors, physical characteristics, how to tell grizzlies apart from black bears, and information for educators.
Photo credit MFWP
The correct scientific name for the species is “brown bear,” but usually only the coastal bears in Alaska and Canada are referred to as such, while inland bears and those found in the lower 48 states are called grizzly bears.
Written by US Fish and Wildlife Service
Grizzly bears are one of the slowest reproducing land mammals. Females do not typically reproduce until they are four or five years old. Grizzly bears mate between May and July, but the female’s body delays implantation of their eggs in the uterus until October or November. If the female has not gained enough fat over the summer to survive and raise cubs, implantation may not occur. A grizzly’s ability to garner enough quality calories through the summer is not just crucial for her survival, but also for her reproductive ability.
Mother bears rear cubs for two to three years. Males do not help raise the cubs. In fact, males can be a danger to the cubs, so females often avoid male grizzly bears while rearing their cubs.
Mating Season: Early May through mid-July
Gestation: Anywhere from 180-270 days, including delayed implantation.
Litter Size: 1-4 cubs, but average is 2-3