Spaying and neutering results in significant public health and safety benefits, particularly the occurrences of dog bites and the transmission of rabies and other communicable animal diseases. It is well documented that unaltered dogs are three-times more likely to attack humans and other animals. California suffers the nation’s highest occurrences of dog bites, animal attacks and attack-related fatalities in the nation and children are the most common victims. (Centers for Disease Control)

Scope of the Problem

Dogs have shared their lives with humans for more than 12,000 years, and that coexistence has contributed substantially to humans’ quality of life. In the United States, there are slightly more than 53 million dogs sharing the human-canine bond, more dogs per capita than in any other country in the world. Unfortunately, a few dogs do not live up to their image as mankind’s best friend, and an estimated 4.5 million people are bitten each year, although the actual number injured is unknown. Approximately 334,000 people are admitted to US emergency departments annually with dog bite-associated injuries, and another 466,000 are seen in other medical settings. An unknown number of other people who have been bitten do not sustain injuries deemed serious enough to require medical attention. Still another group of individuals is not represented by these data, those that incur injuries secondary to a bite or attempted bite. For example, a jogger may trip and break an arm while fleeing from a threatening dog.

Of concern too are the demographics of typical dog bite victims. Almost half are children younger than 12 years old. 6-8 People more than 70 years old comprise 10% of those bitten and 20% of those killed.

Direct costs of dog bite injuries are high. The insurance industry estimates it pays more than $1 billion/yr. in homeowners’ liability claims resulting from dog bites. Hospital expenses for dog bite-related emergency visits are estimated at $102.4 million. There are also medical insurance claims, workmen’s compensation claims, lost wages, and sick leave-associated business costs that have not been calculated.

Intact Animals

Sex differences do emerge from data on various types of aggression. Intact (unneutered) male dogs represented 80% of dogs presented to veterinary behaviorists for dominance aggression, the most commonly diagnosed type of aggression.

Intact males are also involved in 70 to 76% of reported dog bite incidents. The sex distribution of dogs inflicting unreported bites is not known. Unspayed females that are not part of a carefully planned breeding program may attract freeroaming males, which increases bite risk to people through increased exposure to unfamiliar dogs. Dams are protective of their puppies and may bite those who try to handle the young. Unspayed females may also contribute to the population of unwanted dogs that are often acquired by people who do not understand the long-term commitment they have undertaken, that are surrendered to animal shelters where many are destroyed, or that are turned loose under the misconception that they can successfully fend for themselves.

Excerpts from "A community approach to dog bite prevention", American Veterinary Medical Association Task Force on Canine Aggression and Human-Canine Interactions. Full report is available for review here.