This is the time of year in Alaska when the birds are chirping and making their nests, when the first sprigs of green are popping out through the melting snow, and when those big brown bundles are waking up from their winter slumber.

An amazing aspect of bear hibernation is their body's ability to handle the months of inactivity. Generally, they do not eat, drink, urinate, or defecate all winter. Their bodies go into a super recycling state, where their metabolic waste is reused. They may lose hundreds of pounds during this time, as their fat breaks down to give them the calories they need. But their bodies do not lose significant muscle or bone mass through winter, and research has shown that the calcium and phosphorus is recycled back into their bones.