Desert tarantulas are the largest spiders in the world. In spite of how they show us in movies, they are no really dangerous to humans. Tarantulas spend most of their lives time underground in burrows. When the night falls they wait for small animals and insects to wander too close. You are most often to see one during the mating season when the male leave the burrows in search of adult females. Males tarantulas dies 10 to 11 years after mating. However females can live 25 years or more. Tarantulas can mate and lay eggs several times before they die.