Cryptozoology (from Greek κρυπτός, kryptos, "hidden" + zoology; literally, the study of hidden animals) refers to the search for animals whose existence has not been proven. This includes looking for living examples of animals that are considered extinct, such as dinosaurs; animals whose existence lacks physical evidence but which appear in myths, legends, or are reported, such as Bigfoot and Chupacabra; and wild animals dramatically outside their normal geographic ranges, such as phantom cats or "ABCs" (an initialism commonly used by cryptozoologists that stands for Alien Big Cats). These creatures are collectively called cryptids.