Mario Vazquez De La Torre / EPA
Monarch butterflies hibernate at the oyamel forest in Piedra Herrada sanctuary in Temascaltepec, Mexico. Monarch butterflies every year return to these temperate woods.
Check out our Animal Tracks slideshow ... back by popular demand!
Sakchai Lalit / AP
From a baby squirrel to a pile of meerkats, find images of creatures great and small.