Tarantulas (as the term is used in North America) comprise a group of often hairy and very large arachnids belonging to the family Theraphosidae, of which approximately 900 species have been identified. The majority of North American tarantulas are brown. Elsewhere have been found species colored cobalt blue, black with white stripes, yellow leg markings, metallic blue legs with vibrant orange abdomen and greenbottle blue. Their natural habitats include savanna, grasslands such as the pampas, rainforests, deserts, scrubland, mountains, and cloud forests. They are generally classed among the terrestrial types. They are burrowers that live in the ground. The sizes range from as small as a fingernail to as big as a dinner plate. Tarantulas mainly eat insects and other arthropods, using ambush as their primary method of prey capture. Tarantulas are becoming increasingly popular as pets and are readily available in captivity.