What we call tarantulas should properly be called mygalomorphs. In fact, some large hairy spiders have been wrongly called tarantulas. Mygalomorphs have rather poor eyesight and depend on these hairs to detect prey and avoid predators, by air currents and ground movements. Incomplete, no pupal stage.
Hatchlings look like miniature adultes.
Females mature in 3-10 years. Everywhere from the Americas, Africa, across India to SE Asia and Australia. A wide range from rainforests to arid areas. Considered primitive and more ancient than other spiders. For a story of the Spanish origin of the word tarantula see The Tarantula's Burrow .