Can Alligators Hear?
Alligators can hear. The alligator’s hearing is very different from the hearing of humans and other animals. This is because they spend just as much, if not more, of their time underwater. Because of this, their hearing needs to be specially adapted to receive signals through the water and on land. Though not entirely understood, researchers have stated this could happen in several ways.
Jump Ahead
- How Alligators Hear
- Alligator Hearing Under Water
- Alligator Hearing Out of Water
- Things Impacting an Alligator’s Hearing
- Resources
How Alligators Hear
Alligators have shown that they have excellent hearing through both the air and the water. Alligators and most other animals have little hairs on the insides of their ears that pick up on any sounds they hear. Though this is the same for many species, how the sound is transmitted to the animal’s inner ear can differ.
Because alligators spend so much time lounging around underwater, scientists have been prompted to conduct many studies on alligator hearing. Through these studies, they have determined that alligators hear very well underwater and out of the water, and a few reasons why they think this is so.
Alligator Hearing Under Water
One of the ways scientists think alligators funnel sound into their ears underwater is through the bones in their skulls. Another way scientists think alligators do this is through the use of skin receptors in their faces. These receptors are called dome pressure receptors or DPRs. This conclusion was reached because the frequencies used most often in alligator communication are below the optimal hearing range in alligators.
Alligator Hearing Out of Water
Alligator hearing sensitivities in both air and water peak at around 800 Hz. Coincidently, this is also the frequency at which alligator hatchlings chirp. Though their hearing sensitivity peaks at around 800 Hz, they respond to a broad range of tones. Depending on whether the alligator is underwater or above water, the tone ranges that they respond to differ. The tones they can hear underwater range from 100 Hz to 2,000 Hz. Above the water, the tones they hear have a much broader range from about 100 Hz to 8,000 Hz.
Things Impacting an Alligator’s Hearing
Scientists also measured how other things might impact the hearing of an alligator. One of these things was how an air bubble trapped inside the ear might affect the hearing of an alligator. Studies found that these had no effect on the alligator’s hearing. Thus, it is not an important adaptation to their hearing.
Resources
The Journal of Experimental Biology
ALLIGATORS TUNED INTO WATER
http://jeb.biologists.org/content/206/1/9.full
US National Library of MedicineNational Institutes of Health
Amphibious auditory responses of the American alligator (Alligator mississipiensis).
http://www.ncbi.nlm.nih.gov/pubmed/11976890
151st ASA Meeting, Providence, RI
Intensity Of The American Alligator (Alligator Mississippiensis) Vocal Courtship Display: Evidence For Saccular (Non-Cochlear) Hearing In Crocodilian Vocal Communication
http://www.acoustics.org/press/151st/Todd.html
