Think of trying to climb a tree—or doing anything for that matter—without your thumbs. Black and white colobus monkeys get around pretty well in trees, but they do it with practically no thumbs at all. The small bump-like digit that passes for a thumb provides little help in gripping branches. How do the colobus monkeys do it? When they need to jump from branch to branch, they use their four full-sized fingers to form a hook that helps them grasp a branch. Colobus monkeys are great leapers. Territorial males make tremendous leaps as part of a display to ward off other males. They can leap from tree to tree by launching themselves from a high limb on one tree to a lower limb on another. When predators threaten, colobus monkeys drop out of sight into the underbrush below, sometimes from a height of more than forty feet!