Animals "spar" to learn more about pack dynamics then how to actually fight - its about pecking order and mating nothing more.
You realize that is what drives most human violence as well right? Is two guys going at it in a bar to prove hierarchy and impress chicks with their alphaness "sparring" or "fighting?" It is fighting IMO. Most species have ways of ritualizing that fighting so it isn't fatal, dominance can be proven without killing the other member of their own species. Fatal intra-species is unusual, usually associated with wiping out offspring of deposed dominant members of the pack, but chimps have certainly been shown to do it to other groups.
But the "play fighting" that most mammals do does serve a true fighting function as well, ever watch a puppy try to hamstring another? That isn't for another dog that is for prey. Watch a kitten stalk another and pounce on it? That isn't a social dominance training, that is training to be a predator. Sparring leading to functional fighting skills, even if the practice doesn't mimic reality (other puppy is not an elk).