A female dog in heat may be more likely to fight with other female dogs, including other females in the same household. (aapaw.org)
While she may become aggressive toward you or other humans in your household, it's more likely to be directed at other females dogs. (dogcare.dailypuppy.com)
We don't know how he is with cats, but he has been good around other female dogs, a little aggressive around males. (nycshibarescue.org)