If it is necessary to survive, wild animals can kill their own kind. Or maybe just like that.

There are cases when wolves killed their own. In Alaska, as a result of research in the 70 years, 7 deaths of wolves from their fellows were established.
There are also known cases where bears kill other bears, and may also have cubs. And their. Nothing sacred!
With lions is another story, they will always protect their young, but strangers can think without killing. And among fish it is generally an ordinary story. Fish and invertebrates constantly eat individuals of their kind. Pikes, spiders, squid can be continued.
Among cannibals, there is such a feature, the more complex the organism is, the less common is cannibalism. As a rule, cannibolism is a consequence of prion infection. We know of mad cow disease, the cause of which is the constant eating of a cow with bone and meat flour made from the same cow.
In humans, such a disease also occurs and is called Creutzfeldt-Jakob. The consumption of its species in food causes this disease, which is common in New Guinea. We know that eating people is a tradition for the tribes of New Guinea. For today, which is virtually eradicated, but still there are cases.