I wonder what we should call that power-save mode 🤔
this post was submitted on 12 Feb 2026
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That was my first thought.
A bear hunkered down in its winter den is in a different state of energy conservation than hibernation. Instead, bears enter a state called torpor (the adjective for which is torpid).
Unlike hibernation, torpor is involuntary, and primarily triggered by lack of food. This state is also found in other groups of mammals like marsupials, and even in some birds that depend on summer insects.
Another difference between torpor and hibernation is that torpor is a continuous low-energy state, without arousal periods when the animal’s activity spikes.
Torpor is primarily found in black and brown bears. That’s largely because these bears are omnivores with a preference for plants.
You might think that polar bears, living in harsh Arctic conditions, would enter torpor for longer than other bears, but most remain active all winter. Once again, it all comes down to diet.
If lack of food triggers it, what triggers the bears to come out of torpor?
The sound of running squirrels, I guess.
Jokes aside, maybe the smell and environment turning from winter to spring. They mention these happen to black and brown who are omnivorous, so smell of food that's easily accessible is most likely. Just a guess.
sun energy is a form of energy. Sun warms the blood, so they body can spare itself that effort
Suspend-to-RAM?
Hibernation is suspend-to-RAM. Torpor is suspend-to-disk.
S0iX
Actually what is colloquially known as "hibernation" isn't hibernation at all, it's a distinct but trivially different classification that only scientists who specifically study bears have created. Wow!