mouth parts and teeth, such as in whales, vampire bats, leeches, mosquitos, predatory animals such as felines and fishes, etc. distinct forms of beaks in birds, such as in hawks, woodpeckers, pelicans, hummingbirds, parrots, kingfishers, etc. specialized claws and other appendages, for apprehending or killing (including fingers in primates) changes in body colour for facilitating camouflage, disguise, setting up traps for preys, etc. changes in the digestive system, such as the system of stomachs of herbivores, commensalism and symbiosis