Joshua Tree National Park is home to 57 mammal species. Lizards, snakes, and the desert tortoise are among the 46 species of reptiles recorded in Joshua Tree. More than 250 species of birds have been observed in Joshua Tree. Frogs and toads in the desert? Yes! There are two amphibian species in the park. Tarantulas, scorpions, more than 75 species of butterfly ... there are so many invertebrates to see.