 They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms which is reflected in their large diversity of behavior.Almost all known spider species are predators, mostly preying on insects and on other spiders, although a few species also take vertebrates such as frogs, lizards, fish, and even birds and bats.Spiders' guts are too narrow to take solids, and they liquidize their food by flooding it with digestive enzymes and grinding it with the bases of their pedipalps, as they do not have true jaws.