Lots of creatures — this horse is just one example — develop self-destructive behaviors. They'll gnaw on things or do other things that may also soothe them, even if they're self-destructive, which could be considered similar to the ways that some humans cut themselves.
Muchas criaturas —este caballo es solo un ejemplo— desarrollan comportamientos autodestructivos, roerán objetos, o harán otras cosas que los calmen, así sean autodestructivas, lo cual podría considerarse similar a la forma en que se cortan algunos humanos.