grizzly-bears:-north-america’s-furry-giants

Grizzly bears, otherwise known by their scientific name Ursus arctos horribilis, are a subspecies of the Brown Bear. Named after their ‘grizzled fur’, they can live up to 25 years in the wild and range in colour from very light tan (almost white) to dark brown. With short, rounded ears and claws at least 2” long, their large shoulder backbone humps allow them to dig with massive strength. They are avid swimmers and can run up to 35KM per hour – quite impressive given their size! 

In Canada, it’s estimated that roughly 20,000 grizzly bears remain in Western Alberta, the Yukon and Northwest Territories, and British Columbia. 

Social Behaviour

Grizzly bears prefer to be alone (except for their cubs or mate) but will warily tolerate company at concentrated food sources like a coastal salmon stream or a large patch of berries. During these times, they’ll use their posture, facial expression, sound, and smell (ex. droppings, urine, tree rubs) to communicate with each other, including their social status. 

Bear social status usually consists of a ranking that puts mature males on top, followed by females with offspring, single adult bears, and teenage bears at the bottom of the ladder. 

recent study has also linked tree rubbing to increased attraction from the opposite sex. Scientists suspect that through rubbing or scratching their backs on trees, grizzly bears can relay information about their condition, how dominant they are, and information about their genetic makeup. 

Nature’s Foodies 

Although grizzly bears are classified as carnivores, they’re omnivorous. Meat constitutes about fifteen percent of their diet, while the rest is comprised of a selection of plants at specific stages of growth throughout the year. With only seven months to meet their nutritional needs, it’s no wonder that grizzlies have reportedly to eat more than 200,000 buffalo berries in a single day! 

Legume Hedysarum roots, glacier lily bulbs, and spring beauty are also important food sources for grizzlies – specially in late March to mid-May, when bears leave their dens and food is scarce. Other bear favourites include: 

Spring/Early Summer

  • Grasses and sedges
  • Dandelion
  • Clover
  • Cow parsnip
  • Horsetail (equisetum)
  • Deer, elk or moose calves
  • Carcasses of winter-killed ungulates         

Late Summer/Fall

  • Buffaloberry
  • Crowberry
  • Bearberry
  • Grouseberry
  • Currant berries
  • Blueberry/huckleberry (west of Great Divide)
  • Whitebark pine nuts
  • Ants, ant larvae, grubs
  • Ground squirrels and marmots
  • Deer, elk, bighorn sheep, mountain goats
  • Carcasses of elk weakened or injured during the fall rut

(Source: Parks Canada, https://www.pc.gc.ca/en/pn-np/mtn/ours-bears/generaux-basics/grizzli-grizzly)

In the Central Rockies, berries are an important high-quality food source for bears. Due to this, grizzlies often concentrate their food scavenging efforts along dry forest edges and in the open forest, where berries are most likely to flourish. Burned forests are also key sites that support berry-producing shrubs and Hedysarum.  

A Species of Special Concern

Today, prairie populations of the Grizzly Bear are considered locally extinct. Their presence was extinguished by human intolerance, market hunting, rapid conversion of their habitat into farmland, and exacerbated by the loss of important prey like buffalo. 

Due to their sensitivity to human activities and natural events, grizzly bears are listed as a species of special concern by the Committee on the States of Endangered Wildlife in Canada (COSEWIC). 

Habitat loss is the leading cause of Grizzly Bear population decline. Subscribe for updates to stay informed on our latest efforts to protect Canadian wilderness and support the creation of protected areas. 

The post Grizzly Bears: North America’s Furry Giants appeared first on Nature Canada.

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