There are many species of tarantulas and when one thinks of tropical spiders, tarantulas come to mind easily.
Despite their scary appearance, tarantulas aren't all that venomous. Rarely are tarantula bites fatal for humans. There have been some fatal tarantula bites to humans, but only if the person is allergic to the venom.
Most tarantulas stalk and hunt down their prey. They typically feed on insects, rodents, small lizards, and birds.
Tarantulas have lots of predators themselves and so they spend a good portion of their lives hiding.
As far as I know tarantulas are not currently on the endangered species list, but some species of tarantulas may eventually be placed there. For more information please see the article 11 tarantula species are considered for protected status in U.S.