Violence, like beauty, is in the eye of the beholder.
Take a look at the animal kingdom. A lion attackes prey and kills (typically) by going for the throat and suffocate the victim. When hunting in groups, the other lions go for the soft tissue area (stomach/abdomen) and rip the victim apart and start eating it alive. Now we might consider this violent, but the lions won't. It is their nature. A praying mantiss bites of the partner's head after sex...
Snakes devour prey whole as do some other animals. Ever seen a crocodile take down a wildebeast?
I think there is difference between (perceived) violence because of natural instinct and intentional violence (malicious act for the sake of violence).
Yes I agree. There is a difference. It is the intent behind the violence or killing that means everything.