Occam's razor says that most wild animals exhibit preference of what species they'll eat based on taste and availability of food, not because of ethics. I said most because I'm not a wildlife biologist and there always seems to be strange outliers, but I have a hard time believing an omnivore/carnivore, such as a bear, would willingly choose vegetation 100% of the time because of ethics when there's plenty of game of its preference to eat.
>Consider a dog which has been raised around cats, which might hunt a rabbit but not another cat.
Most domesticated dogs that were raised alongside cats won't eat them because they've learned that they're not allowed to. The ones that do attack children and other pets are frequently euthanized.