Other species with known incidence of deafness
Information on deafness in other animals is scarce.
Armadillos: According to anecdotes, these are reported to all have very poor hearing.
Bears: The Maryland Zoo in Baltimore (formerly Baltimore Zoo) has a deaf polar bear named Alaska, 10 years old in 2003.
Birds: There is a report that an (unidentified) study found that deaf wild birds make bad parents, because they cannot hear their offspring calling for food. There are also unconfirmed reports of some pet birds being found to be deaf.
Ferrets: As with many other mammals, deafness in ferrets is fairly common in individuals having whiteness in their coats, though the whiteness need not be total. Many individual deaf ferrets have apparently normal coloration, with only small to tiny amounts of whiteness, often in obscure spots. The Waardenburg syndrome responsible for hereditary deafness in some humans has also been identified in ferrets. A Web site about deaf ferrets is http://wolfysluv.com/deaf.html.
Goats: There is a breed of milk goats called LaMancha, in which all individuals nearly or completely lack the external ear pinna (flap or cup). Contrary to popular impression, however, LaMancha goats are not deaf. They still have an external ear opening, normal inner ears, and hear just fine. For more on them, see here.
Horses: Several deaf horses have been reported. Unfortunately, information is lacking on how the horses became deaf -- whether from hereditary factors, illness, injuries, or other factors.
Llamas and alpacas: These animals, native to South America but used in North America for their wool or as pets or even as herd guards, often have hereditary deafness in white-fleeced individuals.
Mice: There is a strain of congenitally deaf laboratory mice (mutant strain dn/dn) that are used in some laboratory experiments related to deafness. Here is a report:
- Oleskevich, S., Youssoufian, M., & Walmsley, B. (2004). Presynaptic plasticity at two giant auditory synapses in normal and deaf mice. The Journal of Physiology, 560, 709-719.
Minks: As with other mammals, there tends to be a correlation between white coats and deafness in minks. A medical document studying them is:
- Stejskal, Susan Marie. Inherited deafness in the Hedlund white mink: An electrophysiologic and morphologic study. Doctoral dissertation, Michigan State University, 1992.
Octopi, squids, and cuttlefish (coleoid cephalopods): All are truly deaf, completely lacking any kind of acoustic receptors.
Sea lions: The Brookfield Zoo near Chicago, IL, has a deaf sea lion named Harley.
Snakes: In the early 1950s, there were newspaper reports that "research" had shown snakes to be completely deaf. This is incorrect. Although they have no external ear openings, snakes do have internal ears, and can hear some sounds although poorly.