Posted : 2/20/2010 6:02:24 PM
I have a rather *bitchy* female who has experienced high levels of same-sex DA. She can live with a zillion males, and be totally content, but even living with one female can, and has, been difficult for her. Having lived with upwards of 12 dogs of the same breed, I can say with some good faith that same-sex aggression does occur with some frequency, in both males and females. Although I can say that the motives for the same-sex aggression were often quite different between males and females exhibiting the aggression. Males tended to be solely about either breeding rights or defensiveness, while female reasons varied widely.
Both of my females are spayed, and the DA actually increased slightly after the spay (which also has been shown to occur in females - an increase in same-sex aggression). She is a terrier, and pretty much all terrier-like terriers (I say that because there are some breeds named as terriers that really aren't terriers at all!) have higher-than normal levels of DA.
Another link I see in same-sex aggression animals is the comparison between dogs that have been either bred to work as a group, or to work independently. It seems to me that the breeds who have been selected to work independently are also those breeds who often have a higher-than-normal level of same-sex aggression. Breeds selected to work together in pairs, small groups, or large groups like hunting hounds, tend to have a lot smaller dog aggression involved. So really the herding dogs, working dogs, terriers, often tend to be the ones with higher levels of aggression, and the toy dogs and the hounds have lower levels of same-sex aggression (as generalizations, obviously there are caveats).