SFist Photo: Off Leash Dogs "Playing" in an S.F. Park

These two black dogs were seen repeatedly biting the hindquarters of the white one in a local San Francisco park. The white dog might not consider this behavior "play".

San Francisco's numerous off-leash dog areas (shown as the white, green, and black parts of this map) allow for lots of canine-canine interaction. Is the behaviour shown in the photo merely "dramatic-looking, non-injurious squabbling"? Do leash laws actually contribute to this kind of aggression, as suggested by our local chapter of the S.P.C.A.? You make the call.