Friday, June 11, 2010
Depth Information Across Species
Humans make use of number of different sources of depth information in the environment. How about other species though? Many animals have excellent depth perception. Cats leap on their prey; monkeys swing from one branch to the next, a male housefly follows a flying female, maintaining a constant distance of about 10cm; and a frog accurately jumps across a chasm. There is no doubt that many animals are able to judge distances in their environment, but what depth information do they use? A survey of mechanism used by different animals reveals that animals use the entire range of cues described in this chapter. Some animals use many cues and others rely on just one or two. Animals such as cats, monkeys, and humans that have frontal eyes which result in overlapping fields of view, can use disparity perceive depth. Animals with lateral eyes, such as the rabbit do not have overlapping visual fields and therefore cannot use disparity to perceive depth.