Disruptive eye masks are camouflage markings that conceal the eyes of an animal from its predators or prey. They are used by prey, to avoid being seen by predators, and by predators to help them approach their prey.
The eye has a distinctive shape and dark coloration dictated by its function, and it is housed in the vulnerable head, making it a natural target for predators. It can be camouflaged by a suitable disruptive pattern arranged to run up to or through the eye, sometimes forming a camouflage eyestripe. The illusion is completed in some animals by a false eye or false head somewhere else on the body, in a form of automimicry.
Disruptive eye masks are seen on a variety of animals, both invertebrates such as grasshoppers and vertebrates, including fish, frogs, birds and snakes. Eye masks were first noticed by the American artist Abbott Handerson Thayer in 1909, and analysed extensively by the zoologist Hugh Cott in 1940. However, in 2005 the evolutionary zoologist Tim Caro could still observe that the assumption that eye masks served as camouflage had not been tested systematically.