Rock and Roll Gators
Nice teeth! American Alligators have an interesting buoyancy system. Credit:cyclewidow via Flickr
Alligators have an interesting lung musculature. A large muscle attaching from the liver to bone acts like a handle. When it tightens, it pulls air into the lungs and when relaxed, it helps push air out of the lungs. However, if this muscle is severed, alligators are still able to breathe. By implanting electrodes in the muscles of young American alligators (Alligator mississippiensis), Uriona was able to take a better look at the other functions of the lung muscles.
His findings show that the muscles help change the location of air cavities inside the alligator, causing buoyancy changes. For example, when an animal decided to go into a downward dive, the muscle would pull the lungs back, so that the buoyant air isn’t toward the front of the alligator, and the animal is already pointed downward.
This also helps in an alligator roll. Only half of the muscle will tense, pushing the air toward a side of the alligator as it goes into an underwater roll. Alligators are known for their ‘death rolls’ with prey.
Researchers suggest that the main function of the big muscle was for buoyancy control. Through evolution, it also evolved to help with breathing, but this was only a secondary use, explaining why the animals can still breathe without that working muscle.
As said in an article in Science News, “To test the idea, the researchers duct-taped lead shot to the animals’ tails. When the weighted animals swooped, the muscles worked harder. Weighting animals’ noses, to make a downward dive easier, prompted less muscle activity.”
To read the complete article from Science News, Vol. 173, No. 11, March 15, 2008, visit
http://www.sciencenews.org/articles/20080315/fob5.asp
All this reminds me of the Elton John song, “Crocodile Rock”!
Kallen is currently pursuing a Bachelor's degree in Biology and Journalism at the University of Oregon and, of course, writing a blog.