No. 2 in our countdown takes the prize for being the most cute and cuddly of all our tree-dwelling species, according to a small survey of preschoolers. The koala spends nearly its entire life in the stands of eucalyptus trees, where it makes its home. Each koala has its own trees and is only visited by others during mating season, though they may venture to the ground to access a new stand of trees. These animals have a highly specialized diet, eating only eucalyptus leaves, which makes them smell a bit like cough drops. Remarkably, they spend up to 18 hours of each day in an inactive state, either sleeping or resting.