big cats like lions and leopards (not tigers, well actually maybe small tigers like south china tigers, but no way a bengal) have been killed with bare hands. its obviously by the indigenous folk who live/hunt/track in those areas, and its incredibly rare. the method has to do with something along the lines of when attacked by the cat the man shoves his fist down its throat and chokes it out. i believe about a year ago i read a story of a small guy who was approached by a leopard, dropped his machete in preparation, the leopard pounced, then the guy pulled out its tongue. thats some crazy skill and luck considering that cats most often attack undetected.
heres footage from a documentary called Living With Tigers (super awesome doc, well worth it) where the trainer explains how to survive a tiger attack. http://www.youtube.com/watch?v=SdVTaEiQpJo

and no fucking way any human ever kills a giraffe barehanded. even lions have difficulty with that http://www.youtube.com/watch?v=m2FPG2wXhXY

whats funny is how you guys think you could kill a dog with your bare hands. yes some humans can, but take the kangal for example. a dog bred to protect sheep from cougars. not like any of your skinny asses would stand a chance against that thing. im pretty big and strong and i think i would only stand a chance against smaller breeds of fighting dogs. a pit bull may only be 40-80 pounds but it will drag and shake your ass across the floor. dogs dont really kill any humans other than women and children though. they're just not efficient enough to kill grown men much, but a grown man killing a dog bred to fuck shit up is an entirely different thing. of course if a man is trained to do it he would be quite successful.

and fwiw, wolves are pussies compared to elite mastiff variations. i would fuck a wolf up.