Tuesday, September 14, 2010

Animal Hearing Series: Lizards

Back in June, I got a new pet: a bearded dragon named Loki. I really love animals, and Loki is something else. He's funny. He explores everywhere with zero fear. He loves staring out the window at wild lizards, jackrabbits and quail.
Loki
Bearded dragons can sense light when they're asleep, so when his light goes off, we turn off the lights in the room. Any light in his cage/"vivarium" will wake him up at that point, and trust me, you may not think a lizard can glare, but they can. What I found most interesting, though, was that while light will wake Loki up, sound won't. We can have the television on very loud and sound can be coming from the room, out in the living room, etc., and he won't wake.

That got me interested in how well lizards hear. He does seem to react to sounds when he's awake, but is he just seeing things and reacting to those?

In my research I realized that animal hearing is really interesting, so I decided to make a weekly series about animals and their hearing.

First up: lizards!

Loki has a visible ear (actually his tympanic membrane). It looks like a hole in his head, outlined below in purple:


Lizards' tympanic membranes might look like Loki's, or they might look like an iguana's, almost level with the skin. Some are even like human's, recessed deep in the skull. They don't have ear flaps like humans do. The tympanic membrane picks up sound vibrations from what the reptile is in contact with - the ground, a basking rock, etc.

Most lizards seem to hear about the same. (Even ancient ones!) The green iguana and other lizards with tympanic membranes can pick up sounds in a range of 500-4,000 Hz. They show peak sensitivity at 24 dB. Compare that with humans: our typical range is 20-20,000 Hz and our sensitivity is at 120 dB. So, lizards cannot hear as well as a human, but they are probably more sensitive to ground movement than we are. 

Sites Referenced
Reptile Channel
Reptile Hearing - Melissa Kaplan
San Diego Zoo

9 comments:

  1. He is cute, enjoy your new pet.

    And interesting info on hearing and pets!

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  2. Knowledgeable article. Thanks a lot to sharing it.

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  3. Aw wow, i love your website and these posts! Loki is cute, LOVE HIM!

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  4. This actually came in handy. I wanted to put in a high frequency device to repel mice (hate the idea of killing them) and I was worried it would hurt my little gecko. I watched her when I plugged it in, but much as your article suggests, I don't think she can even hear it. Thanks for the post! Yea, science!

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  5. Nice post! Bearded dragon lighting is very important. Lighting can also affect their health if not handled properly.

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  6. This was great info for the project I'm working on as well as gaining general info on my beardy!! :)

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