If you mean pure strength (ie pulling power), the horse is a lot stronger than a gorilla. Its not even close - you know that video of a female orangutan out pulling a sumo wrestler? A female horse would casually walk away dragging that sumo wrestler as if he wasn't even there. Horse power measures sustained output (ie a twelve hour day); a horse can put out much more power than that for a few minutes.
great post.
but im'a have to call bullsheet on the horse "out pulling" a strong man. I've personally seen Strongmen pulling 747's, freight trains, and big ass Fire Trucks. I even saw this arm wrestling champ on youtube holding two 1500cc Harley Davidson Motorcycles at full throttle from launching with out breaking his gable grip.
You think a Horse can do that mayne? and mind you two 1500cc Harley's put out the equivalent of 200 HP HORSE POWER each 2/3.14 x(H _1) / {2 H2.17} =500+ HORSE POWER!
Try finding me 500 horses that can keep two full throttle Harley's from launching?