Why do dogs attack a dog when it is hurt ?

When a dog is hurt bad , by being hit by a car, looses a fight with another dog, gets snake bit etc… and is crying and in pain , why do other dogs ,weather there is one or a dozen , jump on the one that is hurt and crying?

I have 2 dogs, one is 7 years old and the other a half grown pup a year old , the pup was kicked by a cow yesterday and today is pretty stove up and stiff, nothing is broken and there was no blood , but when he moves wrong he cries, the other dog seems to be ready to jump on the pup every time, like the crying is a signal to attack or something.

It’s not just these 2 dogs. I have seen this 'behavior; many times before , every time there is a dog really hurt and or scared crying and yelping, any dogs close around jump on it and really seem to want to kill the poor thing .

I will not allow the ‘healthy dog’ to get any where close to the pup and had to smack him once last evening when he tried getting around behind me to get at the pup. Generally they are best buddies ,playing together ,eating from the same dish sleeping on the same doggie bed etc…

Just a bit of background info. We live on a cattle ranch and there is pasture all around our place, my dogs usually ignore the cows but yesterday a small bunch of yearlings can running and bucking past the yard and the dogs just joined in . except those yearlings hadn’t invited the mutts and took exception one kicked the dog snot out of the pup . That is one lesson about cows he won’t be needing a refresher course in, I’d be willing to lay odds on.

Just a WAG, but dogs, being pack animals know that they cannot afford to find food for an injured member of the pack. Therefore the injured is removed from the pack and cannot slow it down.

SSG Schwartz

Thanks , that makes sense when I think about it that way.

Anecdotally, my ex inlaws in Ireland used to help breed hunting hounds. They told me that runts and injured pups were regularly torn apart and eaten by the other hounds, and this behaviour was tolerated by the breeders as it strengthened the pack.

(Which information came as rather a shock, given that I was caring for one of the puppies at the time, and it was astonishingly cute.)