 Wild-caught tarantulas are often mature males because they wander out in the open and are more likely to be caught.Like other spiders, tarantulas have to shed their exoskeleton periodically to grow, a process called molting.A young tarantula may do this several times a year as a part of the maturation process, while full-grown specimens only molt once a year or less, or sooner, to replace lost limbs or lost urticating hairs.