Black bear cubs are mostly born in middle to late January which is the hibernating season of black bears. They are completely dependent on their mothers when they are born, as they have almost no fur on their bodies. The weight of a newly born cub is not more than a pound, and they are born in litters of two to four cubs each. A newly born cub is not even able to crawl for the first few days after birth.
As cubs are dependent on their mother for food and other needs, the mother bear would sleep only a light sleep. She keeps her mind functioning and her body temperature would be in such way that she could keep her babies warm. When they need to be fed, she is in a state to feed them while half asleep. Usually cubs are found under the body of mama bear in order to keep warm during harsh winter weather. She usually hugs her babies in between her legs and chest, also keeping her mouth towards her chest so her breath can keep the babies warm.
The newly born cub only food is their mother’s milk. Their mouth is naturally made in a way suitable for drinking milk from mother bear. As they are not able to hunt or eat anything else, they need to survive only on mother’s milk. That is why; cubs will not go into hibernation and will keep on feeding on their mother from time to time. It has been observed that a mama bear is fully aware of her kids’ needs even while hibernating. If a cub moves away from her nipples, she will prod him back to make sure they do not starve. To help growing bears defecate, she will lick them just like cats and dogs do to their babies. Cubs will swallow their waste product in order to preserve any possible nutrient and it also keeps the den clean during bear’s hibernating season.
Cubs will grow really fast and they do so by avoiding hibernation period. They will keep busy in nursing and defecating which will help them grow soon. According to researchers, cubs tend to make interesting humming sound while they are feeding on their mothers. This helps mama bears know that their babies are still feeding and not to move while sleeping.
It is also a common fact that many cubs will not reach their grown up age because of the harsh weather and cruel predators. Though female bears tend to mate every two years yet this frequency may change with changing weather and environment. The biggest trouble cubs have to face is the flooding of den during hibernating period as they may drown or get chilled. The baby bears will gain weight of 2 – 3 pounds in one month and they will have thick fur on their skin by then. Up until April, a baby cub gains weight of 10 pounds only by feeding milk of her mother.