DEN CAM OBSERVATIONS

This black bear mother is preparing for the birth of her cubs by gathering balsam fir branches that she then chewed up for more bedding.

As labor began she clenched her jaws and flexed her head muscles.

Twelve hours before delivery our mother bear began slamming her body against the side of the den.

A half an hour before birth she begins licking herself.

Birth! Listen for the sound of a cub and the welcoming grunts of the mother. Notice the bedding made of chewed up logs.

Mothers immediately lick the birthing fluids off each cub and warm it.

To warm the cubs, mothers tuck their cubs underneath them and breath on them with her head tucked under her chest. The cubs are not hibernating. Their job is to nurse, sleep, and grow quickly.

When the mother had to urinate or defecate, she backed into a corner—or to the entrance. The cub cried for the mother to come back and keep it warm. Notice the trail of urine at the end of the video.

To get water, mothers ate snow.

Mothers also ate icicles to get water.

When cubs’ eyes opened around 6 weeks of age, they began to play. They played with their mothers.

Cubs played with each other.

In fact, all family members played, including this mother with yearlings. The way they expended energy on play when they had no food made us think how important play is to family relations.

A bonding activity that may also have other benefits was reciprocal tongue-licking that all family members did in dens and out of the dens as the cubs grew up.

Grooming was frequent. Mothers groomed their cubs and their yearlings, and yearlings groomed their mothers.

Yearlings suckled in the den every day, making this pulsing hum—even though they got little or no milk. In spring after emergence, some well-fed mothers resumed lactation and nursed their yearlings right up to the day of family breakup in May or June.

As one of these yearlings makes the suckling sound, the mother is eating a yearling’s fecal plug that rolled back into the den after the yearling backed to the entrance to defecate. Fecal plugs are mainly cells that slough off the digestive tract during hibernation and build up in the colon.

Again as we hear a yearling suckle, the mother is removing her right rear foot pad to expose the new one that is growing beneath it. Mothers sometimes also help their yearlings remove footpads.

Both mothers and young went through stages of sleep that included the eye movements and twitches of REM sleep. Does that mean they dream?

Could dreaming explain why this mother woke up from REM sleep blustering forward as if disoriented before turning toward the den entrance? Does the fact that she immediately calmed down when she realized nothing was there suggest that she can separate bad dreams from reality?