Bird spiders (Theraphosidae) form a well-known family of spiders within the suborder arachnids (Mygalomorphae). Many species reach a considerable body length compared to other spiders. A number of species are kept as pets in a terrarium.
Despite their size, tarantulas are relatively harmless. Most species are not very fast, not toxic to humans and not aggressive, a bite in humans is similar to a wasp sting. There are, however, exceptions that are particularly toxic and fast and, moreover, attack immediately, which is why they are regarded as aggressive. Bird spiders are feared by many people because of their size and strong hairy body.