The den of a black bear in Minnesota has a web cam.
We listen for cub sounds. The team is trying to get rid of the buzz so all can hear better. To answer a common question, the light is invisible infra-red. The camera converts it to visible light for us to see on the internet, but it does not illuminate the den. On the other hand, darkness is not important to hibernation. Many bears build above ground nests and spend the winter in broad daylight. Some get covered by snow at times, but they give birth and raise cubs successfully anyway.