Tarantulas are among the largest spiders in the world. Tarantulas are among the largest spiders in the world. In contrast to many other spiders, they do not spin a web, but lay in wait for their prey – especially frogs, mice and birds. People don't have to be afraid of them. Tarantulas may have a strong bite, but they are good-natured, and their venom is weaker than that of bees.