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Size of lunch dictates force of crunch

February 12, 2013
Big bite may not be best bite

Nicholas Gidmark tends a research subject. Bite force varies with morsel size. If a morsel is too large or too small, the jaw muscles do not move through their optimal length and may not crush it. A middle-size morsel is just right. Credit: David Orenstein/Brown University

Nicholas Gidmark, a postdoctoral researcher in the Department of Ecology and Evolutionary Biology is part of a team to determine that even in the same animal, not all bites are the same. A new study finds that because the force in a muscle depends on how much it is stretched, an animal’s bite force depends on the size of what it is biting. The finding has direct implications for ecology and evolution.

The nuance comes from a well-understood phenomenon of physiology that had never before been measured in terms of a living animal’s bite force: The force a muscle can exert depends on how long that muscle gets preparing for the chomp.

Gidmark and his co-authors hypothesized that the length-force relationship could have culinary consequences. For an individual animal, too much stretch (for a big piece of food) or too little stretch (for a small piece of food) would weaken the bite compared to the stretch required to crush an optimally sized morsel. To test this idea they conducted a series of experiments with black carp, which normally dine on fresh escargot and have conveniently simple jaws.

Read more in David Orenstein's article on bite force in animals.