Lions will kill hyenas just because they hate them sure they compete for food but they will go miles out of their way to make a point, dolphins will kill for sport so will cats, don't tell me you've never seem a cat pack around a mouse all day and keep it alive so they can play with it, chimpanzee's and monkeys will kill because they are bored among other reasons.
I lived on a farm as a child, I've seen a lot of anamals kill just because they can I've seen them kill out of instinct as well, I've seen the difference. Some of you need to get out of the city and see how nature works because I see a lot of flawed perceptions.
My horse hated this boxer that lived down the road, never had a issue with our dogs. Anyway that dog was outside their property on a trail and my horse stomped that dog into a puddle with me beating the hell out of it the entire time, he didn't give two shits about what I wanted he was killing that dog. So far as I know the only contact he had w the dog is when we rode by he had no reason to kill it so yeah animals are sold short on intelligence but people overlook other aspects as well, I'm not saying they should be abused but shooting a large cat is never a big deal.