Research has established a number of factors associated with aggression, including the following:
Chaining and tethering
Chaining, tethering or tying a dog to a stationary object causes a dog to act viciously toward people.
- 26-28% of dogs involved in fatal attacks were chained at the time. Journal of the American Veterinary Medical Association: Dog Bite Related Fatalities from 1979 through 1988 by J. Sacks. R. W. Sattin, & S. E. Bonzo. Volume 262, pages 1489-1492.
- Since 2003, at least 450 Americans have been injured or killed by chained dogs; the majority of the victims were children. Chained Dog Attack Summaries by PETA.
- Chaining or tethering has been declared illegal in many communities. See Table of State Dog Tether Laws by Animal Legal and Historical Center, and Dogs Deserve Better, a website that advocates against chaining and penning dogs. California was the first state in the nation to prohibit chaining. See Health and Safety Code Section 122335, the California law prohibiting tethering. A minority of USA states have anti-chaining laws (see, for example, Texas) or currently are considering the enactment of such laws. See Dogs Deserve Better: U.S. Anti-Tethering Legislation By State.
- Chaining also is inhumane. Chaining and Tethering ;by the Humane Society of the USA. Chaining by PETA.
- See The Public Safety and Humane Implications Of Persistently Tethering Domestic Dogs, by New Mexico Department of Public Safety (2008), for an in-depth review of this issue.
Male dogs are more aggressive than females, and most of the aggression is by intact males. Male dogs accounted for 70% - 87% of the attacks studied, and 60% were unneutered males.
- Readings in Companion Animal Behavior. Victoria L. Voith & Peter Borchelt. (1996: Trenton: Veterinary Learning Systems) pp. 226, 235.
- Public Health Reports: The Ethology of the Dog Bite. A. M. Beck, H. Loring, & R. Lockwood (1975).
- A Study of Animal-to-Human Bites by Breed in Palm Beach County, Florida. D. L. Moore. 1987.
- Journal of the American Veterinary Medical Association: Selecting Pet Dogs on the Basis of Cluster Analysis of Breed Behavior Profiles and Gender. B. L. Hart & L. A. Hart (1985, Volume 186, pages 1181-5).
Pet store dog or puppy mill dog
Dogs from pet stores and "puppy mills" have a high incidence of dominance-type aggression and defensive or fear aggression.
- Early Experience and the Development of Behavior by James Serpell and J. A. Jagoe, in The Domestic Dog, Its Evolution, Behavior, & Interactions with People. James Serpell, editor. (1995: Cambridge University Press).
- The Puppy Report. Larry Shook. (1992.) Lyons & Burford, publishers).
Inadequate socialization prior to the age of 14 weeks results in a higher incidence of fear aggression.
- Science: Critical Periods in the Social Development of Dogs. by D. G. Freedman, J. A. King, & O. Elliot. (1961, volume 122, pages 1016-1017).
- Genetics & the Social Behavior of the Dog. J. P. Scott & J. L. Fuller. (1965: Chicago: University of Chicago Press).
Inadequate training and discipline result in dominance aggression.
- Effects of Owner Personality and Attitudes on Behavior by Valerie O'Farrell, in The Domestic Dog, Its Evolution, Behavior, & Interactions with People. James Serpell, editor. (1995: Cambridge University Press).
Poor health results in aggression.
- Clinical Behavioral Medicine for Small Animals, by Karen Overall (1997: Mosby Year Book, Inc.), p. 2.
- See the studies of the Chow, in which approximately 50 genetic diseases have been shown to result in aggression.
- Control of Canine Genetic Diseases. George a. Padgett. (1998: ; Howell Book House) p. 199.
- Genetics of the Dog. Malcolm Willis. (1989: Howell Book House).
- Behavior Problems in Dogs. William E. Campbell. (1975: Goleta, CA: American Veterinary Publications, Inc.) p. 88.
- Dog World: Thyroid Can Alter Behavior by Jean W. Dodd, D.V.M. (October 1992) pps. 40-42.
Pain and fear
Pain and fear result in aggression.
- Clinical Behavioral Medicine for Small Animals, by Karen Overall (1997: Mosby Year Book, Inc.)
- Readings in Companion Animal Behavior. Victoria L. Voith & Peter Borchelt. (1996: Trenton: Veterinary Learning Systems)
Submitting to the first vaccination after the first 8 weeks of life results in greater aggression.
- Early Experience and the Development of Behavior by James Serpell and J. A. Jagoe, in The Domestic Dog, Its Evolution, Behaviour, & Interactions with People. James Serpell, editor. (1995: Cambridge University Press), pp. 97 et seq.