To continue the previous post’s theme of “bear cub 101” I will talk about mothers with older cubs. All bears keep their cubs for several summers, with the black bear being the shortest interval at 1.5 years. Grizzly bears usually keep their cubs for 2.5 years and separate sometime during the 3rd summer. Many bear experts believe that bears keep their cubs longer in places where conditions are harshest, so one wouldn’t expect coastal grizzly bears of the Katmai Coast to keep their cubs any longer than 3 summers because of the rich food sources such as salmon and other seafood like clams and beached whales, but this isn’t the case. I often see mothers kick their cubs out at the beginning of the 4th summer, and sometimes even into the fifth summer! As I watch these bears I have come to realize that being a bear here is not necessarily easier than a place with less food like Yellowstone, Denali or the arctic because of the density of bears. To survive here you have to learn more than what to eat and where to find it- you have to learn how to get along with lots of bears packed into a concentrated food source like a salmon stream that has enough food for lots of bears in a small space. Keeping your cub an extra year or two may be necessary to master these social skills that other bear populations do not have to learn to such a degree.
Second Summer Cubs-
Often referred to as “yearlings” cubs in their second summer are 1 1/2 years old. They look like miniature versions of adult bears, and lack the dark coats and corona (light collar) of spring cubs. These cubs are still very vulnerable to predators like wolves and other bears, and are very dependent on their mothers. It would be extremely unlikely for cubs of this age to survive on their own without their mothers.
Third summer cubs-
Cubs of this age are often kicked out as early as May as their mothers come into estrus (heat) and can mate again. If the bears have matured well and learned from their mothers, it is possible for these bears to make it on their own, but that first summer is always a huge challenge. Large bears can still kill cubs of this size, but they are normally fast enough to outrun them. We had two families of third summer cubs. Amazingly one of the mothers had 3 cubs! It is rare to see 3 third summer cubs because the average litter size is 2, and the mortality rate of cubs is very high. Only a very good mother can support 3 cubs for this long.
Fourth Summer Cubs- These bears are very lucky to have an extra year with mom. The mothers are still nursing, and do so until they are finally kicked out, but are usually capable of digging their own clams, and catching their own fish. They often wonder off and away from their mothers and interact with other bears, but the mother will come to the rescue if things get dangerous.
This year I saw something I have never seen before. A large male was following the mother at very close range (sniffing distance) and the cub was still very close, but the mother did not try to flee or defend the cub. This happened for around two weeks. I guessed the mother had come back into estrus but for some reason didn’t exhibit the usual anger and normal ferocity that scares the cubs onto their own. This thought vanished when I saw the mom and cub alone later and she was still nursing. To my understanding a female in estrus is no longer lactating. This situation is still a mystery to me and other bear guides.
What a summer for mothers and cubs!