Last week I gave you an update on the orphaned cubs we rescued a year ago, and I reported that the cubs weighed only 12 lbs. (5.45 kg) when we rescued them, but they now weigh 175 lbs. (79.54 kg). Is this normal; do Kodiak bear cubs in the wild gain that much weight in one year? The answer to this question varies and is dependent on many factors, including the mother’s physical condition. Was she able to eat enough berries and salmon to provide her with adequate nutrition to care for her cubs, and did she catch so many salmon that the cubs were able to eat a few of the scraps to supplement the milk she fed them? As with humans, some sows are better mothers and providers than others. Older sows with more experience tend to do a better job than young sows providing for their young. If the mother cannot find enough food for herself, she usually drops one of the cubs. Sows often leave the den with three or four cubs but may only have one or two by the end of the first summer. This sounds cruel, but if the mother senses she cannot feed three cubs, she must sacrifice one to save the other two.
Under normal conditions, a Kodiak bear cub’s weight doubles every two months during the first year. By their second summer, yearling cubs weigh approximately 135 lbs. (61.36 kg). By the time they are two-and-one-half years old, the males begin to outgrow the females, and weights may vary greatly. Females average 212 lbs. (96.36 kg) And males average 225 lbs. (102.27 kg). Females reach their full adult size at approximately five years when they weigh between 350 and 500 lbs. (159.09 – 227.27 kg). Males continue to grow, gaining approximately 100 lbs. (45.45 kg) per year until they are eight to ten years old and weigh 500 to 1000 lbs. (227.27 – 454.54 kg) Kodiak bears gain weight and add fat in the summer when food is abundant and then burn off this fat during hibernation.
The largest Kodiak bear on record lived in the Cheyenne Mountain Zoo and weighed 1670 lbs. (757 kg.). In the wild, Kodiak bears are not easy to weigh. Biologist Vic Barnes set out to answer the question, “How big do Kodiak bears get?” With the assistance of hunting guides, he obtained the weights of several large boars and sows shot during spring and fall hunts. The largest three boars weighed 1245 lbs. (566 kg), 1483 lbs. (674 kg), and 1519 lbs. (690.5 kg). The largest female weighed 767 lbs. (348.6 kg).
I plan to do more bear posts over the next few weeks, so don’t hesitate to ask me a question or tell me something you’d like to know about Kodiak bears. If I don’t know the answer, I’ll research it.
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