Why do some animals have such huge muscles when they only eat plants with little protein?!
Answers:
The amount of muscle tissue a species has is mostly genetically controlled. The idea that more protein gives larger muscles is largely an advertising scheme to sell questionable dietary supplements.
http://www.hsph.harvard.edu/nutritionsou…
http://www.sciencebasedmedicine.org/?p=9…
the animals that have been eating plants have been doing it for generations so their body adapts to little protein.