How young can they go into heat?
I know it's a stupid question, but I don't know much about female dogs.
My neighbor's son has been visiting him with his seven-month-old, unspayed female Boxer, and the neighbor has been bringing her over to my yard to play with Karloff, who is nine months old and unfixed. He loves playing with her, but I have to keep scolding him for humping. He has been good about not doing this with the many dogs he plays with every day in the park, mainly because I have scolded him the few times he has tried, but with the Boxer his hormones really kick in.
I asked my neighbor if she could be in heat, and he said his son insists this isn't possible, but he couldn't explain why his son believes it's impossible. She is due to be spayed next month, though this isn't relevant to my question.
Kyra, female GSD, whelped 6/15/10
Karloff, male sable GSD, whelped 6/30/08
Tuco, male black GSD, 7/17/97--8/13/08, RIP
Ada, female GSD mix, RIP