Melissa
Kaplan's
Herp Care Collection
Last updated
January 1, 2014
Did you hear the one about...?
©1994 Melissa Kaplan, News from the North Bay, 1(1):15
Years ago I found a reference to snakes' ability to hear, but, failing to write it down, could never locate it again. Seigel and Collins, in their Snakes: Ecology and Behavior, were not enormously enlightening: "Although there is meager behavioral evidence for hearing of airborne sounds, there is physiological evidence from several species in six families. In addition, attachment of the quadrate to the inner ear suggests that vibrational stimuli could be transmitted by the jaw. However, vibrational cues could just as likely be detected by tangoreceptors on the venter of the snake" (New York: McGraw-Hill, Inc. p. 121, 1993), which most of us already know ('hearing' by feeling vibrations transmitted up from the ground into the belly muscles).
I was pleased to see a short note about snake hearing ability in this month's The Vivarium (6[3]:24-25). In the "Ask the Experts" column, Winston Card responds to a snake hearing question by explaining that, while snakes lack external and middle ear structures (including the tympanum, or ear drum), they do have inner ear structures which have been shown experimentally to receive airborne sound waves.
Thus, like many other animals, snakes have two ways of detecting sounds: earthborne and airborne. The earthborne vibrations are passed through the belly muscles to special receptors along the spine and thus transmitted to the brain. Airborne sounds are transmitted to the lung from the skin receptors to the eighth cranial nerve and inner ear.
Most snakes can hear a person speaking in a normal tone of voice in a quiet room at a distance of about 10 feet (3 m). Two of my snakes have always responded to my calling their names; it's nice to know I wasn't imagining it!
Update
1999
In February
1999 I received a note from Jamey, a visitor to my site, telling me about another
website he found on snake hearing. The article, Shhh! The
Snake Can Hear You, goes into more detail on the mechanics of how snakes hear.
Update
2010
In June 2010, Laura pointed me towards this journal article:
Snake
bioacoustics: toward a richer understanding of the behavioral ecology of snakes.
Q
Rev Biol. 2003 Sep;78(3):303-25.
Young
BA. Department of Biology,
Lafayette College Easton, Pennsylvania 18042, USA.
Snakes are frequently described in both popular and technical literature as either deaf or able to perceive only groundborne vibrations. Physiological studies have shown that snakes are actually most sensitive to airborne vibrations. Snakes are able to detect both airborne and groundborne vibrations using their body surface (termed somatic hearing) as well as from their inner ears. The central auditory pathways for these two modes of "hearing" remain unknown. Recent experimental evidence has shown that snakes can respond behaviorally to both airborne and groundborne vibrations. The ability of snakes to contextualize the sounds and respond with consistent predatory or defensive behaviors suggests that auditory stimuli may play a larger role in the behavioral ecology of snakes than was previously realized. Snakes produce sounds in a variety of ways, and there appear to be multiple acoustic Batesian mimicry complexes among snakes. Analyses of the proclivity for sound production and the acoustics of the sounds produced within a habitat or phylogeny specific context may provide insights into the behavioral ecology of snakes. The relatively low information content in the sounds produced by snakes suggests that these sounds are not suitable for intraspecific communication. Nevertheless, given the diversity of habitats in which snakes are found, and their dual auditory pathways, some form of intraspecific acoustic communication may exist in some species. PMID: 14528622
That reminded me that I had another link to more research by Bruce Young, including this article: Auditory Atavism and Integrated Pathways for Hearing in Snakes (PDF)
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Auditory Atavism and Integrated Pathways for Hearing in Snakes (PDF)
