A hibernating bear can go months without eating, drinking or using the bathroom

Once a bear settles into its winter den, it stops eating, drinking, urinating and defecating, and an undisturbed bear can stay that way for months.

Instead of getting rid of waste, its body recycles it. Bears break down urea and reuse the nitrogen to maintain muscle and organ tissue, and a plug of feces, hair and bedding forms in the gut during hibernation.

By spring a bear may have lost up to a third of its body weight. Kidney researchers study hibernating bears to learn how they pull this off without lasting harm.

One more surprise: "black" bears aren't always black. Plenty of them are brown, cinnamon or even blond.

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A curious black bear up on its hind legs, tugging a strand of glowing string lights off a snowy spruce by the light of a single cabin window.

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