Wild Fact #979 – Why Goldilocks Shouldn’t Have Eaten the Porridge – Black Bears
While working in Ontario, I helped contribute to a program called Bear Wise, which was basically an education first approach to teaching people how to co-exist with bears. See, there was an issue of bears feeding on food sources in people’s yards such as dog food, bird feeders, apple trees, etc. Besides simply explaining to people to remove these sources it is also a good idea to explain a bit about bears so they understand why they act this way.
Today’s Wild Fact may help explain why food is so important to bears. It is absolutely crucial for black bears, and especially the females, to be healthy for winter hibernation. Why is it so important that female black bears are healthy for the long winter hibernation? Wow, great question, I wish I would have thought to ask that. Well, black bears exhibit something called embryonic diapause. Wait! Before we get into what this means lets back up to the nicer climates of June to August. During these nice and warm months (is it sad that I am already missing summer?) black bears will find, court and mate with each other. If successful the female bear will have a fertilized egg (this isn’t a sex-ed class so I am not going to go into details); however, due to embryonic diapause the embryos will not begin to develop until the mother begins to hibernate in the den. Due to this delay the total gestation period for the black bear is around 7 or 8 months but actual embryo development is only 60 days. So what does this have to do with bears getting enough berries throughout the year? Well, as a safety precaution, if a female bear is not fat enough to sustain herself as well as produce and feed her cubs during hibernation then the implanted embryo’s will not develop and no young will be born that year. Even though, the bear has successfully mated in the summer the pregnancy test will still be negative if she is not healthy enough to take care of her cubs and herself. This evolutionary advancement ensures that only healthy bears are born and is a perfect example of the famous “Survival of the Fittest” theory.
Do you have any interesting stories of black bears feeding in your backyard?