Hundreds of species of insects, arachnids and other invertebrates find a home in the unique ecosystems of Montezuma Castle National Monument. These include harmless tarantulas as well as highly venomous black widow spiders and bark scorpions. However, these often misunderstoood desert inhabitants pose little threat to humans. The invertebrates found at Montezuma Castle and Montezuma Well reveal extraordinary evolutionary adaptations for survival in an arid desert environment.