Name one animal which kills its own kind???

Human beings kill for other reasons besides food. Sharks kill other sharks for food. And coming back to human beings....it's really bad don't you think that they kill for all the reasons that they do...most of them are silly. I wish people would think about what they were doing. Animals killing other animals or even people can be justified as their need to survive. But humans killing other humans for personal reasons...unjustifiable!

is it frogs?