What is one factor that influences how an animal obtains its food?

Factors would include:

Speed to Catch - Faster animals would be more adapt to catching prey.

Ability to Digest - Teeth as well as specialized digestive organs such as a cow's stomachs.

Size - Larger can fest easier on small.

Flight or No Flight

Eyesight

Abilities to Stalk Prey

Specialized Organs such as a jellyfishes tentacles.

Almost any characteristic of an animal can be used as a factor to determine how it catches or attracts food. These can be just shear size, strength, or stealth.