Unlike all other wildlife, early January marks the time when Pennsylvania's black bears are giving birth to their young, which weigh less than one-half pound, according tothe Game Commission.

"Despite the time of year, survival of these newborns is relatively high, and a litter can range in size from one to five, with the average being three," said Mark Ternent, Game Commission bear biologist. "Amazingly, this entire process occurs while bears are in hibernation.

"In Pennsylvania, bears den up and become dormant during the winter. Females, which will be producing cubs, may begin hibernating as early as mid-November. Hibernating bears, unlike other hibernating wildlife, are awake and aware of their surroundings, but usually will not leave a den site until spring. Body temperature, respiration and heart rate might decline, but not noticeably. They do not urinate or defecate while dormant.

At the time cubs are born, females will groom their cubs daily, so hibernation for bears is more like a prolonged rest than a deep sleep that is common of other hibernators, such as woodchucks or chipmunks."

Ternent noted that, on warm, winter days, male bears may emerge from a den and even move around, but they will return to a den. He said that these activity bouts are not actually foraging trips.

"In rare instances, where food sources are readily available, a bear may visit the food, but it is usually only temporary," he said.

Pennsylvania's black bears -- numbering nearly 15,000 – are powerfully-built animals. Most adult bears weigh between 140 to 400 pounds, but rare individuals may exceed 800 pounds. Extremely agile for their size, bears can reach speeds of 30 miles per hour, can climb easily and swim well. Mainly nocturnal, bears sometimes feed and travel by day.

In late winter, February through mid-March, the Game Commission will use telemetry equipment to locate dens of radio-collared female bears. Then, armed with tranquilizers, agency biologists and Wildlife Conservation Officers will gather data about the adult bear, as well as the cubs.

"After sedating the adult, we weigh it, check its radio collar and ear tags and replace them if necessary, and then place ear tags on each of the cubs," Ternent said. "Once the data collection is complete, we return the female and its cubs to the den, and leave the area. Den visits are necessary to monitor bear reproduction levels in Pennsylvania."

In spring, when the bears leave the den, the female continues to protect the cubs, sending them up trees if danger threatens. By fall, cubs weigh between 60 and 100 pounds and, in most cases, despite their ability to survive on their own, den with the adult female for their first winter before separating the following summer.

For more information, visit the Game Commission’s black bears webpage. The page also features a series of online videos of adult and young bears.

1/26/2007