Zoo grizzly bear sisters cozy up for torpor — not hibernation

If you were going to nest for the next five months, you'd want the coziest bedding possible. That's what these grizzly bear sisters, Nova and Nita, have been doing at the Maryland Zoo. Because zoo bears don't need to fully hibernate, they instead enter torpor, a lighter state, where their body temperature, metabolism, and oxygen levels drop for the winter. Nova and Nita have settled in to snore the cold months away.