Scientists think the tarantulas use chemicals to tell which frog is which. They have seen young tarantulas pick up small frogs. The young tarantulas touch the frogs with their mouths. Then they put the frogs back down. They do not eat or bite them. Microhylid frogs, like the dotted humming frog, make chemicals in their skin that taste bad. Scientists think this might be why the frogs and spiders started living together.