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Published on: December 16, 2022
Functional evolution of the feeding system in rodents
Philip G Cox1, Emily J Rayfield, Michael J Fagan
1Hull York Medical School, University of Hull, Hull, United Kingdom. philip.cox@hyms.ac.uk
Plos One
|May 5, 2012
Summary
Rodent jaw muscles evolved for gnawing and chewing. Finite element analysis reveals squirrels excel at gnawing, guinea pigs at chewing, and rats are versatile, high-performance generalists.
Area of Science:
- Biomechanical analysis
- Mammalian evolutionary biology
- Craniodental morphology
Background:
- Rodent masticatory musculature exhibits diverse adaptations for incisor gnawing and molar chewing.
- Three main conditions (sciuromorph, hystricomorph, myomorph) describe masseter muscle expansion in rodents.
- Understanding these adaptations is key to rodent feeding ecology and evolutionary success.
Purpose of the Study:
- To investigate the biomechanical implications of sciuromorph, hystricomorph, and myomorph jaw morphologies.
- To determine the feeding specializations (gnawing vs. chewing) associated with each rodent masticatory condition.
- To compare the feeding efficiency and versatility across different rodent morphologies.
Main Methods:
- Finite element analysis (FEA) was employed to model and analyze masticatory biomechanics.
- FEA was applied to skulls and musculature of representative species: a squirrel (sciuromorph), guinea pig (hystricomorph), and rat (myomorph).
- Biomechanical efficiency for incisor gnawing and molar chewing was quantified for each morphology.
Main Results:
- Squirrels demonstrated higher efficiency in force transmission for incisor gnawing compared to guinea pigs.
- Guinea pigs showed greater efficiency in molar chewing compared to squirrels, aligning with their diets.
- Rats exhibited superior feeding efficiency and versatility, outperforming both squirrels and guinea pigs without compromising biting force.
Conclusions:
- Rodent skull and masticatory muscle morphology facilitate specialized feeding strategies, such as squirrels as gnawers and guinea pigs as chewers.
- Rats represent highly efficient and versatile generalist feeders, contributing to their widespread ecological success.
- FEA provides valuable insights into the functional adaptations of masticatory systems in rodents.
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