In the late fall frogs bury themselves in the mud out of reach of frost to hibernate. Frogs are cold blooded animals so their body temperature drops as the temperature drops. For this reason frogs have to hibernate and they do this at the bottom of ponds, on hillsides or in other places. They stay here until next spring. Frog bones form a new ring every year when the frog is hibernating.
Scientists can count the rings to discover the age of the frog.
Captive common frogs have been known to live for 12 years. Some frogs have been known to live up to 20 years but few wild ones live this long. Recent reports show that many amphibian populations are undergoing declines and even extinction. These losses are important both because of the reduction in biodiversity and because amphibians are sensitive biological indicators of the health of the environment. Although habitat destruction is a major reason for declines, there may be additional factors such as chemical pollution, increased UV-B radiation, fungi, parasites and predation.