Why don't they get scratch marks?

I was watching my boys play this morning & Levi was getting very ruff with Jordan (it happens every couple of months Levi's had enough of being pushed around & gets agressive when playing). He was holding him on the ground rabbit kicking his back & I could hear his claws making contact. My question is how is it that they don't get hurt? If that were my arm I'd be all cut up & bleeding all over. I'm just amazed at how they will scratch each other & they have no marks at all.

I think they're just playing, so the nails are contracted. Buffy and Willow do it to each other all the time, and when they break apart, they always come back together again (well, Willow might try to run off, but Buffy almost always comes back, eager to play some more)

Agreed with the above. During true play, which might look rough, the cat's claws aren't fully extended. Really, they're not trying to hurt the other cat.

Yeah, if your cat had his claws out all through play, he wouldn't have playmates for long