It protects the eyes without completely cutting off vision. Most frogs have a disk of skin behind each eye. Each disk is called a tympanum, or eardrum. Sound waves cause the eardrums to vibrate. The vibrations travel to the inner ear, which is connected by nerves to the hearing centers of the brain.
Most frogs have a delicate sense of touch.
It is particularly well developed in species that live in water. The tongue and mouth have many taste buds, and frogs often spit out bad-tasting food. The sense of smell varies among species. Frogs that hunt mostly at night or that live underground have the best sense of smell. Male frogs of most species have a voice, which they use mainly to call females during the mating season.