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Bear Update: Yearling black bears and August forecast 2002



Black Bear Researcher

Yearling Explosion

This summer Whistler is experiencing a slight explosion of yearling bears – one year old bears which have been pushed out from their family bond by their mother.

Family break up is a naturally occurring event in the bear world. It’s supposed to happen. Yearling bears, 18-19 months old are small (30-40 pounds in the ski area; 50-70 pounds in the valley) resembling boarder collie to German Shepherd-sized dogs. Seemingly helpless, small yearling bears are supposed to be on their own. If you see a yearling, enjoy the experience and leave it alone. Yearling sightings do not need to be reported as "bears in distress." Yearlings are eager, resourceful, tough, and as always, adaptable.

You can report sightings/activity to the Whistler Black Bear Project at 604-902-1660, as the information is useful in monitoring kinship relations of local bear families.

Bear Family Biology

Mother bears raise cubs for 17-19 months from birth in January, allowing mom’s to produce litters every two years. After the cubs first winter of hibernation (cubs do not hibernate when they are born) they emerge as 16-month-old yearlings in April.

The mother breaks up the family during mid-May through mid-June (occasionally early July) in response to the presence of adult males. After the mother is away from her yearlings she begins to leave scent behind, indicating her availability to mate.

To separate from her young she begins to distance herself and act uninterested in their activities. Yearlings follow and she gets aggressive. She distances herself continuously and soon the yearlings get the message. They KNOW it’s time to leave their mother.

In the ski area, mothers raise 1-2 cubs and throughout the valley 1-3 cubs. Daughters remain in their natal range (area of birth) and sons are forced to disperse after break-up.

Sons are forced out of their mother’s territory to eliminate potential inbreeding (with mothers and sisters), competition for food, and potential cub predation.

During the mating period (June and July) adult males may kill cubs to induce the breeding cycle of mothers. Mothers may experience many aggressive encounters by males but are generally successful in protecting cubs from males in that the survival rate of cubs with their mother is 95 per cent.

Daughters are allowed to remain in their mom’s territory until they mature (at four years) then either mother or daughter will shift territory activities to overlap. In nine years (1994-2002), there has been only one case where a black bear cub was found abandoned or separated from his family. He was approximately 30 pounds in July and did survive on his own without any human intervention.