Ears indeed. In 1912 Johan Erik Vesti Boas published his Ohrknorpel und äusseres ohr der Säugetiere; eine vergleichend-anatomische Untersuchung (Ear cartilage and outer ear of mammals, a comparative anatomical study). Beautifully illustrated, Boas' book takes us through a host of mammal ears from rodents, to whales, kangaroos, pigs, bats, primates, and yes, even humans. There are some very nice cartilage spreads as well which we have included in our in our Flickr photostream but for now I will show some of my favorite pinnae (outer ear) pin-ups!
|Find the ear of the tiny tenrec here!|
|Ooh, there's a pika ear in here!|
|Can you spot the capybara ear?|
The study of the mammalian ear is important to evolutionary biology in that is an exemplar of the concept of exaptation which describes how traits from one organismal group are co-opted to function differently in another group. In this case, the jawbones of reptiles were co-opted to form the ear bones of mammals commonly known as the hammer, anvil and stirrup. 
Next time you are enjoying the company of fellow mammals, human or otherwise, take a closer look at their ears and think of yourself as Dr. Boas (with a cabinet full of ear specimens!) carefully examining and comparing one of the more functional pairs of our anatomies: the ears.
--Bianca Crowley, BHL Collections Coordinator