Male leopard goes to eat leopard cubs hiding in a tree. Mother leopard says, "oh no you didn't!"
The economics of the situation: male leopards will kill the cubs of other males to increase the chance that their own DNA will be passed on. It's a competition for limited resources and survival of the fittest.
Note to self: if I ever go on safari, don't hide in a tree from a leopard and don't use a cameraphone to shoot video.