The green tree frogs will eat insects and spiders. However, they can also eat smaller frogs and even small mammals. The frog's teeth are not made for cutting up their prey. This means that the prey has to fit inside their mouths in order for the frog to eat it. Many frogs will stick out their tongues at prey. The green tree frog's tongues, as with many frogs, are very sticky. The prey will be stuck and will be eaten. The green tree frog will use their tongues on small prey. For larger prey, they will jump on top of it and force it into their mouths using their hands.