Female dogs that have not been spayed or sterilized have natural tendencies to protect their ability to ensure the continuation of the species. Some of these tendencies translate into behaviors that humans don't anticipate or appreciate in a canine companion such as aggressive fighting. Learning these behaviors can guide owners in the decision to spay or leave a female dog intact.
Her Estrous Cycle
A female dog that is not spayed will go through a heat cycle every six to eight months. This is a period that tests the mettle of a female dog owner. Not only is the female dog, or "bitch" as referred to in canine breeding terms, extremely needy, but she is also highly difficult to calm. Her natural desire to breed overrides any other inclinations, and she will remain unsettled until she gets some action or the three weeks of her great willingness is concluded. Female dogs in heat become escape artists looking to mate and also are magnets for every other male dog in the smelling vicinity. She will readily thrust her hindquarters in the face of any male dog approaching her, thus making the daily neighborhood walk a potentially embarrassing event for her owners.
This is another naturally-occuring behavior most often associated with male dogs. However, females -- including those spayed -- are just as likely to lick their genitals to please themselves. They have no shame in this and are quite likely to engage in this behavior publicly.
In biological terms, a female dog's job is to produce puppies. Even when an intact female has not mated, her body can mimic pregnancy. Symptoms include a swelling of the breasts, a leaking of milk, bloating in her belly and nesting behaviors including placing favorite toys in her bed. A female dog experiencing a false pregnancy is a confused animal and is more likely to exhibit aggressive behaviors.
In general, girl dogs just don't like other girl dogs. Whether it is a threat to mating potential or a natural protection of their own ability to conceive and raise puppies, female dogs that have not been spayed rarely make happy housemates. They are overtly aggressive to each other and to the offspring of their rivals.
Amy M. Armstrong is a former community news journalist with more than 15 years of experience writing features and covering school districts. She has received more than 40 awards for excellence in journalism and photography. She holds a Bachelor of Arts in communications from Washington State University. Armstrong grew up on a dairy farm in western Washington and wrote agricultural news while in college.