Lifespan: 20-25 years
Wild Diet: Anything from insects to berries to fish to moose
Zoo Diet: Carnivore meat, fish, vegetables, crickets
IUCN Status: Least Concern
Habitat/Range: Varies from dense forest to alpine meadow to arctic tundra in western Canada, Alaska, Wyoming, Montana, Idaho and Washington
Characteristics: Grizzly bears are generally larger and more heavily built than other bears. Grizzly bears have long curved claws, humped shoulders, and a face that appears to be concave. Grizzlies have very strong legs. They are typically 6.5-7ft tall and weigh 450-600 lbs.
Behavior: Grizzlies are solitary mammals can run up to 35 mph for short bursts. They are mostly nocturnal (active at night) and typically sleep in dens (caves, hollow logs, or holes). Grizzlies, like other bears who live in the wild go into torpor (tor-pur) during winter months when food is scarce. This is not a true "hibernation" as with some rodents and bats, but their metabolism and heart rate lowers, resulting in lower activity levels. In full torpor some bears may experience a deep sleep while others are awake and moving around from time to time; they typically don't eat, drink or get rid of wastes until Spring.
Reproduction: Mating season is typically early May through July with a gestation of 63-70 days. Litter size is usually 1-3 cubs born in January and February, while the mother is denning. Newborn animals are short in the neck, long in the legs and have long, furry hair. Young stay with their mothers for 2-4 years.
Conservation: Historically grizzlies were abundant in the San Juan Mountain of southwestern Colorado and there were around 50,000 in North America. But by the mid-19th century, killing by ranchers and government trappers reduced the population to a few shy survivors. In 1952, after a federal trapper killed an adult female north of Pagosa Springs, wildlife officials declared grizzlies extinct statewide.
Then, in 1979, along the Continental Divide south of Pagosa Springs, an "extinct" Colorado grizzly was surprised on its day bed by a bow hunter. The bear, perhaps feeling cornered, attacked. The hunter was knocked to the ground and severely mauled, but managed to stab and kill the bear with a hand-held arrow. And with that controversial incident, grizzlies were gone once again from Colorado.
Today, there are 1,000 - 1,200 grizzly bears remaining in five separate populations in the lower 48 states. In Alaska, there are thought to be over 30,000 individuals. Reported sightings of grizzlies in Colorado occur on a regular basis, but no confirmation has been made. Cinnamon phase black bears are often mistaken for grizzlies though there are distinct differences in their size, shape and behavior. Grizzly's come into conflict with man due to garbage, pet food and bird food. This often leads to the lethal removal of the bear. In addition, some brown bears are accidentally killed by hunters who mistake them for black bears, which are legal to hunt. They are also declining in number due to habitat loss. The struggle for grizzlies and humans in North America continues as humans learn to live with these large predators, reserve space for them in the wild and have the willingness to change our behaviors to accommodate their presence.