Wow! Reading all these replies makes me think that I have an atypical grey. I have been fostering on and off for about three or four years so Sally came in as a foster. Mensa was very happy to have another grey in the house. Always has been. My fosters never seemed to last more than a month, most only a week or two before they were adopted. So when Sally didn't leave...... There were never any problems between the two. Mensa was just happy to have a sister he could run with outside. I do have to muzzle him though when they are outside. He likes to play rough and I found out the hard way how thin greyhound skin can be.