Welcome to Seven Sizes of the Dog, an educational website intended to appeal to two audiences: the scientific community and the dog fancy so that one community can learn from the other—and at the same time learn from researcher/author Russell Schexnayder in his own words.

Schexnayder’s work on the seven sizes of the dog is a culmination of more than 25 years of study. His theory on the way the number of the repeated DNA sequencing on one gene determines which of the seven sizes of the dog any pup will grow up to be should change the way the dog fancy classifies the size varieties of dog breeds. Dog buyers and breeders can look to his research and classifications to gain new information.

Scientists can also learn how his theory results in tremendous size diversity as well as from the natural population structure of single-size dog varieties—particularly where breeders do not artificially increase their range—and what the structure of local inter-breeding mammal populations should look like. Learn more about Schexnayder.

Navigating Through This Site

  • For context, we strongly recommend navigating from left to right in the top menu. Start by reading the “Introduction,” continuing with “Teacup Breeders” in the “Teacups” drop-down menu. From there, we encourage you to learn more about Schexnayder in the About section and about future efforts to expose his additional research findings on the Donate page.
  • The Introduction begins with Schexnayder’s conclusion that there are seven sizes of the dog, refuting what some dog breeders and breed clubs espouse, consequently leading to misinformation that results in tremendous health risks to dogs of specific breeds. Using historical information—from ancient to more recent from knowledgeable breeders—Schexnayder strengthens his position that there are indeed seven sizes of the dog while identifying and explaining the gene responsible for the doubling of the dog’s weight range from one size variety of a breed to the next.
  • Throughout the site, Schexnayder discusses ways in which breeders use incorrect breeding techniques and introduces us to breeders who have the correct genetics in their breeding stock, subsequently producing healthier dogs of sizes unrecognized by national kennel organizations and individual breed clubs.
  • On the Teacup Dog Health page, Schexnayder points out the health issues of some breeds of dogs when breed clubs refuse to acknowledge there are size varieties not defined in their breed standard. As a result, they do not provide proper guidelines for breeders and buyers to use.