Do furry animals bruise? [Have you ever seen a bruise on a shaved animal?]?

There are two hypotheses about why bruises are so visually salient on us.





Hypothesis 1: It is just what happens to mammalian skin when hit hard enough. If this is so, then dogs get bruised just as strongly as you would given a similar impact, except that they're furry, so you never see their bruises.





Hypothesis 2: Animals with bare skin like us (and other primates with bare spots on the face, chest or rump) have evolved to enhance the display of the bruise. It would be more like blushing, reddening with anger, and other color signals we "communicate" to others. Perhaps by "purposely" displaying the bruise, others can come to our aid. At any rate, if this hypothesis were the case, then a similar impact to you and a dog would lead to a much more salient bruise on you than the shaved dog. There could still be a bruise on the dog under the skin, since there will still be an injury. The question is the extent to which the animal's skin enables the bruise to be seen by us
Do furry animals bruise? [Have you ever seen a bruise on a shaved animal?]?
I'm a veterinarian and I've seen LOTS of bruises on animals- dogs, cats, birds, horses, etc. Trauma to the skin leads to bruising, sometimes even when the "trauma" is from surgery, an IV catheter, or other medical procedures.
Do furry animals bruise? [Have you ever seen a bruise on a shaved animal?]?
A bruise is just blood under the skin, I've seen it on dogs.


It shows up as a bluish darkish area.
Reply:I don't know who proposed hypothesis 2, but the person doesn't seem very smart and doesn't know much about human or animal behavior.





Bruises have a biological cause (coagulation of blood under the skin due to ruptured capilaries) and all animals bruise wether or not it's visible. Since a dog is bred by humans to have certain traits, how would a dog be bred to show an injury as communication unless humans actively selected for it?





Besides the fact the example you provided isn't very applicable to the animal kingdom, there is a reason most animals (including humans) try their best to mask injury. You "communicate" scenario isn't consistent with what we know of human or animal behavior and directly tries to use "group selection theory" as it's basis. This has been proven to be wrong over and over again.
Reply:Yes. Any mammal can bruise. It is just blood that bleeds to the surface, and is in the flesh or under the skin. You just don't see it on animals with hair, because it is covered. You can certainly see it on light covered horses and cattle though.