Chipmunks are small squirrel-like rodents of the genus Tamias. They are native to North America and Asia. Tamias is Greek for "storer," a reference to the animals' habit of collecting and storing food for winter use. The genus includes twenty-five recognized species, with one species in northeastern Asia, one in eastern North America, and the rest native to western North America. They are also called "striped squirrels", "chippers", "munks", "timber tigers", or "ground squirrels". Chipmunks have an omnivorous diet consisting of grain, nuts, birds' eggs, small frogs, fungi, worms, and insects. These small mammals fulfill several important functions in forest ecosystems. Their activities harvesting and hoarding tree seeds play a crucial role in seedling establishment. Chipmunks play an important role as prey for various predatory mammals and birds, but are also opportunistic predators themselves, particularly with regard to bird eggs and nestlings. Chipmunks construct expansive burrows which can be more than 3.5 m in length with several well-concealed entrances. The sleeping quarters are kept extremely clean as shells and feces are stored in refuse tunnels.