Here are a few ways to rephrase that sentence, with slightly different nuances:
More direct:
* Dogs that chew bones tend to be more aggressive than dogs fed only meat.
* Bone-chewing dogs show more aggression compared to dogs on a meat-only diet.
Focusing on the comparison:
* A dog that chews bones exhibits a higher level of aggression than one that eats only meat.
* Compared to dogs that are fed a meat-only diet, dogs that chew bones are more aggressive.
Slightly more formal:
* Canines that engage in bone-chewing behavior demonstrate greater aggression than those maintained on a solely carnivorous diet.
Which rephrased sentence works best depends on the specific context and the point you want to emphasize.