Research by Holy Cross Biologist Disproves Belief that Dogs are Juvenile Wolves

Sophisticated 3-D Technology Aids in Analysis of Domestic Dog Evolution

April 5th, 2011
Kristine Maloney


According to a recent study by Abby Drake, Ph.D., a research assistant in the biology department at the College of the Holy Cross, the evolution of man’s best friend—the domestic dog—is unique to that of wolves.

For a long time, dogs were viewed as “juvenile” wolves, meaning a dog’s development did not advance as far as a wolf’s development, from an evolutionary standpoint, says Drake. This seemed to be reinforced by a dog’s playful demeanor and specific physical attributes, including floppy ears and dome-shaped heads.

However, Drake’s paper, published in the March/April 2011 issue of Evolution & Development, dispels this belief and, in fact, proves that dogs are not paedomorphic—they, as adults, do not resemble wolf pups—through a sophisticated three-dimensional comparison of dog and wolf skulls.

To accomplish this, Drake utilized a Microscribe 3-D digitizer, a fiber optic arm equipped with a stylus that recorded the three-dimensional coordinates (x, y and z) of 64 landmarks on the skulls of more than 600 adult dogs and 400 wolves, with the wolves ranging in age from pups to adults.

“I used it to capture a three-dimensional, ‘dot-to-dot’ image of each skull, which allowed me to quantify and describe its shape,” explains Drake.

The resulting computer-generated images were scaled to the same size, allowing Drake to examine the differences in the shapes of the skulls. Her analyses revealed that the skulls of adult dogs—with specific attention to such features as the face and braincase— do not morphologically resemble those of wolf pups, so dogs cannot be considered juvenile wolves.

“One of the main objectives of this study was to compare adult dogs to wolf pups. I made the three-dimensional data on their skulls the same size, so that the only difference between the skulls would be due to shape variation. As it turns out, they weren’t the same shape,” concludes Drake.

Drake, who received her doctorate in evolutionary biology in 2004 from the University of Massachusetts-Amherst, specializes in geometric morphometrics (3-D shape analysis) and evolutionary biology with a focus on vertebrate skulls. Through her research she investigates the evolutionary and developmental processes that bring about biodiversity.

Last year, she published a study with Chris Klingenberg of the University of Manchester comparing the skull shapes of domestic dogs with those of different species across the order Carnivora, to which dogs belong with cats, bears, weasels, and even seals and walruses.


Notes for Editors:
A copy of the paper “Dispelling Dog Dogma: An Investigation of Heterochrony in Dogs Using 3-D Geometric Morphometric Analysis of Skull Shape” is available at: http://aves3d.org/shared/470agd.pdf

For more information, high resolution images, or an interview with Drake, please contact Kristine Maloney, director of national communications and media relations, at 508-793-2419 or kmmalone@holycross.edu.




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