Natural History

Tarantulas spend most of their time underground in burrows (a tarantula burrow can be identified as a 1-2 inch hole covered with some fine strands of silk). In the winter they plug the opening with rocks and silk and remain in a relatively inactive state, living off their body reserves. Except in the mating season, tarantulas remain close to their burrows, and prefer to hunt at night. To eat, they grab and inject their prey with venom which paralyzes them and begins the process of digestion.
 

Tarantulas are not dangerous to humans, though they can deliver a painful bite if provoked. In addition to venom, tarantulas are equipped with barbed hairs on the top of their abdomen. When threatened, it can brush these hairs onto it's attacker. These hairs are irritating, and because of the barbs, are difficult to remove.
The spiders typically mature around 10-12 years of age and can live up to 20 years. Once mature, a male will leave his burrow in search of a mate (the tarantulas you see on the roads in Arizona are usually males cruising for females). Upon finding the burrow of a female spider, the male will announce himself by tapping and plucking the silk at the entrance. After mating, the male beats a hasty retreat lest the female kill and eat him, though even if successful, he usually does not survive much longer.