COMMUNICATION. “Although most mammals still use olfaction as a social communication tool (with the probable exception of cetaceans), the production of sometimes elaborate vocalizations/calls, the mammalian cochlea and three-ossicle middle ear, and the development of patterned, brightly colored fur and skin point to the importance of auditory and visual communication among mammals.”
http://onlinelibrary.wiley.com/doi/10.1111/joa.12440/full