I was surfing the pictures to try to find the one I had seen years ago of a big sulcata with his sides crushed in from being rammed by another big sulcata. Couldn't find that picture, but found this article, which I thought was very interesting:
http://www.britishcheloniagroup.org.uk/testudo/v6/v6n3mcarthur.htm
http://www.britishcheloniagroup.org.uk/testudo/v6/v6n3mcarthur.htm