An interactive model of human and companion animal dynamics: The ecology and economics of dog overpopulation and the human costs of addressing the problem

Companion animal overpopulation is a problem of human creation with significant human costs that can only be addressed through human action. A model was constructed to understand the dynamics of canine overpopulation and the effectiveness of various policy options for reducing euthanasia. The model includes economic and ecological factors in human and dog populations. According to the model, a "no-kill" society is an achievable goal at an acceptable human cost. Spay/neuter programs were generally found to be the most effective, with increasing adoptions also being an effective option. However, spay/neuter policies need to be evaluated over a very long time horizon since full impact may not be achieved for 30 years or more. Spay/neuter efforts can have a large impact even if they only effect a small portion of the human population. Adoption and spay/neuter programs were found to work well in combination, and to continue being effective as society approaches "no-kill" dynamics.