Bear Reproduction, Babies, and Lifespan

Bear Reproduction, Babies, and Lifespan

Female Kermode bears reach sexual maturity between the ages of 2 and 9, while males sexually mature at three to four years of age. However, they keep developing until 10 to 12 years and continue growing until they can dominate juvenile males without fighting.

The males do not participate in caring for the young, but they do indirectly help by warding off new males and eliminating competition for food and space. The only time male and female spirit bears cohabitate is during breeding season from June to mid-July.

Female Kermode bears stay in estrus throughout the mating season until copulation. Pregnant females typically give birth every two years but sometimes have a 3 to 4-year gap between litters. Their gestation is very unique as the fertilized egg begins to divide until the save is spherical, known as a blastocyst.

However, this phenomenon is so special that the embryo’s implantation into the uterus wall does not occur just yet. Instead, the embryo’s development ceases, which is called delayed implantation or embryonic diapause.

Finally, in November, the blastocyst implants itself in the uterus wall; this is around the time that the female will enter her den to hibernate. If she is able to build up a good supply of fat deposits during the summer, the embryo will develop to completion, and cubs will be born in late January or early February in the warmth of the female’s lair.

Unfortunately, if she is not able to build up enough fat reserves, she will not be able to sustain her offspring until spring, and the pregnancy is terminated.


The litter size ranges from 1 to 5 cubs, though they give birth to 2 to 3 cubs on average. Like black bear cubs, Kermode bears typically weigh 0.5 to 1 pound at birth. They are born blind and inhabit the den with their mother throughout the winter. When they emerge in the spring, the cubs weigh between 4 and 11 pounds.

The female spirit bear is quite protective of her cubs while she teaches them how to survive. Cubs mimic their moms in every way, learning from her every move, including how and where to find food and escaping danger. Cubs take pleasure in wreaking havoc in any situation, although it appears they are motivated more by hunger than mischievousness.

The cubs are usually weaned after 6 to 8 months; however, they will remain with their mothers through their second winter until they reach 17 months old. After that, cubs will gradually add solid food to their milk diet. When the mother bear’s offspring no longer relies on her for sustenance, she will chase her cubs out of her territory.

Depending on the abundance of food, they may weigh anywhere from 15 to 100 pounds.


Kermode bears have a relatively long lifespan of 25 years.

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