Sled Dog Evolution
By: Michael K. Guy, DVM, MS, PhD, Vice President and Clinical Veterinarian
Archeologists working on a remote island in northern Siberia have found what may be the earliest known evidence of breeding dogs for a specific purpose – and that purpose was to produce sled dogs!
Zhokhov Island is an island in the East Siberian Sea, about 500 miles north of the Siberian mainland. However, Zhokhov Island was not always an island. 9,000 years ago, sea levels were lower than today and Zhokhov Island was connected to the rest of Siberia via a land bridge. The hardy folk that lived in this area are the only known people to have successfully hunted polar bears without a firearm; they also followed and hunted the large herds of caribou across Siberia during their annual migrations. Researchers suggest that this demand for long-range mobility created the urge and demand to breed dogs specifically to pull their food-laden sleds across the snow.
People have been domesticating dogs for 15,000 years or more; but in the beginning this simply involved the ‘taming’ of those wild wolves that were docile enough to approach camp and be comfortable around humans. Herding dogs, i.e. – dogs specifically created for herding, are known to have originated in the Near East about 7000 years ago. But the Zhokhov Island sled dogs are at least 2000 years older.
There are two interesting items from the fossil record that suggests these animals are dogs rather than wolves. Fossil bones from 11 individuals found on Zhokhov Island are from canids weighing between 16 to 25 kg, much smaller than an average wolf of 40 to 80 kg, but, as it happens very close to the ideal body size for a sled dog of 20 to 25 kg. Sled dogs larger than 25 kg are too big to dissipate body heat rapidly enough and tend to overheat when on the trail.
A second interesting item from the fossil record that suggests these animals were purpose-bred dogs and not simply domesticated wild wolves. Skulls from two canids found on Zhokhov Island have traits and morphometric measurements similar to those of Siberian Huskies and very dissimilar from wolf skulls.
Remains of wooden sleds and dog bones have been found on Zhokhov Island since the archeological dig began in 1989. However, it was not until the bones from several individuals were analyzed that indicated that all of the dogs were within a similar size range, and a similar size range to modern sled dogs. These dogs also had other traits more like modern Siberian Huskies than wolves, suggesting that this is the earliest known evidence of dogs being bred for a specific purpose.
Grimm, D. (2017). Earliest evidence for dog breeding found on remote Siberian island. Science. doi:10.1126/science.aan6897
Grimm, D. (2017). Siberia yields earliest evidence for dog breeding. Science. doi:10.1126/science.356.6341.896
Pitulko, V. V., & Kasparov, A. K. (2017). Archaeological dogs from the Early Holocene Zhokhov site in the Eastern Siberian Arctic. Journal of Archaeological Science: Reports, 13, 491-515. doi:10.1016/j.jasrep.2017.04.003
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