Question: Why does my dog go for other male dogs but is fine with female dogs?

Laurel Fogarty answered on 20 Jun 2010:

That is all to do with pheromones. Animals emit chemicals constantly (even humans do) these are called pheromones. Your dog can smell them from other dogs and knows exactly what each smell means. Your dog will be able to smell another male and will see him as competition. If he smells a female he will not be as aggressive in case she is the love of his life 🙂