Communication and Perception
Hearing, olfaction, touch, and vision are all important to some degree in prototherians. Hearing and sight are well developed in platypuses and moderately well-developed in echidnas. The sense of touch is perhaps most important to a platypus that is searching at the bottom of a stream for food or an echida that is rooting through the earth for termites or worms. Platypus bills and echidna snouts are extremely sensitive organs that are essential to effective foraging. Platypuses may even use electrical stimuli to locate prey. Olfaction is well-developed in echidnas and may be used in individual recognition. Prototherians occasionally produce some simple vocalizations, but their function is unknown.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; acoustic