Animals have adapted in a variety of ways to cope with life in the rainforest. A loud call is very useful for animals, especially birds and monkeys. This is due to the fact that leaves act to block and muffle sound, so a louder call is needed to attract mates, alert to predators and declare territories. Colour vision is also seen amongst many ape and monkey species living in the forest. They use this to pick out fruit from leaves. As fruit is often more nutritious and less toxic than some leaves. Climbing is also an essential adaptation to many rainforest organisms, and can be seen in reptiles, insects, and mammals. The forest floor has very little food compared to the canopy, so most organisms are adapted to climb to the top to acquire food or escape danger.