ROCHESTER, N.Y. (WROC) - While not many of the animals you’ll see at the zoo will end up hibernating, because that would make for a boring zoo, those who work there like the zoo’s Veterinarian Dr. Christopher McKinney share an interest in how hibernation really works. "It's a state of decreased metabolism that an animal goes through when conditions aren't great. So around here that would be our winter period where animals, everything just slows down their heart rate. They don't keep themselves as warm. They don't breathe as much. Their whole body just really slows down for that whole period," says Dr. McKinney. But it can look very different depending on the animal, like the groundhog will spend nearly the entire season with their body near freezing and their metabolism shut down only waking every few weeks to occasionally snack while bears on the other hand. "Bears or have a very light sleep. They actually don't eat at all through their entire hibernation, but it's a much lighter sleep. So if something were to happen, they can wake themselves up from that," says Dr. McKinney. "Bears, bats as well, will try to build extra fat stores to keep them going through the winter since they're not eating." It’s this type of behavior too that gives us the National Parks Service annual fat bear weekcontest to see which bears have packed on the most pounds for the winter ahead. For bears as well, the hibernation period can also double as a pregnancy. "Bears actually do so they mate in the fall but they don't actually become truly pregnant so where the embryo is now growing that doesn't happen until they're actually hibernating for the winter so they actually have the babies while they're hibernating," Dr. McKinney says. Hibernation isn’t just for mammals either, reptiles and amphibians also undergo this seasonal slow down, and while they share some similarities, how and where they hibernate can be much different than their mammalian cousins. "Amphibians, so they will actually burrow a little into the ground but they'll actually freeze during hibernation and they can concentrate the glucose or sugar in their bloodstream and it actually acts as a natural antifreeze so it prevents their internal organs from freezing but all their muscle tissue and everything is actually frozen during that time period," says Dr. McKinney. And yes, it is true. Turtles, when they are hibernating, do in fact breathe through their butt. "Turtles will do is called butt breathing so they have a cloaca," Dr. McKinney says. "They can actually absorb oxygen through that and while they're hibernating they barely need any oxygen when their metabolism is so low."