Whale Ears Hear

Most whales still have the mammalian conceit of an ear canal and other recognisable features of land-mammal ears, but the nature of sound in water means that whales have evolved a free-floating series of bones inside their heads which isolates sound direction despite the vibration of their own bodies caused by the sound waves travelling through water.
http://news.nationalgeographic.com/2015/03/150311-whales-hearing-underwater-ears-echolocation-ocean-animals-science/

http://www.dosits.org/animals/soundreception/mammalshear/hearingincetaceans/

The ear wax recovered from dead whales can be used to age the whale, and increasingly for more complex research on their chemical intake, hormone production and such.

http://www.livescience.com/39727-blue-whale-earwax-chemical-archive.html