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Musk Ox Teeth

by Poul Henrichsen

All About the Musk Ox

This article originally appeared in the Alaska Science Forum on April 21, 1980.

    Humans are not the only ones to have dental problems. The muskox, so well adapted in many ways to life in harsh environments, has more than its share of dental anomalies. Here in Alaska a large number of muskoxen have rotated teeth of a kind similar to that occurring in young people and which they correct by wearing braces. Some muskox have peg-shaped teeth, and some have teeth that are congenitally missing.

    In Greenland, I worked with muskoxen for the Danish government. After examining skulls found in the field and in museums, I became aware of the muskox's dental irregularities. Since last autumn I have been working on the "Muskox project" at the University of Alaska, Fairbanks, and have been able to examine the teeth of 13 animals here. In one animal the outermost front teeth had never developed, in four animals these teeth were peg-shaped, and in three of the oxen one or more premolars were rotated approximately 90 degrees.

    In humans it has been shown that similar dental anomalies are influenced by genetic factors. Based on the similarity of the dental anomalies in human and muskox, I believe that the anomalies in muskoxen also are genetically influenced. In Greenland the frequency of the dental anomalies is very great in some areas while very low in others. Therefore, it appears that the muskox in Greenland occur in several discrete populations.

    All the muskoxen currently in Alaska are the descendants of some 30 animals caught in Greenland in 1930. In that part of Greenland where these oxen were captured missing, peg-shaped and rotated teeth are found in about 30% of the animals. That the same dental anomalies are still found in muskoxen in Alaska today after nearly 50 years of living under conditions quite different from those in Greenland, is strong evidence for genetic rather than environmental control of dental anomalies in muskoxen.

    A major reason for examining the teeth of muskoxen is that differences in the incidence of tooth anomalies in various parts of the muskox range, from Alaska through arctic Canada to Greenland, can show whether muskox herds exist isolated from one another or whether there is continuous exchange between herds. If animals readily move, then similar tooth anomalies should be found in all parts of the muskox range.

    About 25% of white North Americans have disoriented teeth, and about 5% have missing or peg-shaped teeth (wisdom teeth excluded). Since controlled breeding experiments with humans are not feasible, not enough is known about the genetic and environmental factors that may cause tooth anomalies in humans. Consequently, knowledge gained from controlled breeding experiments with animals sometimes results in better treatment of human disabilities. Further investigation into the causes of dental anomalies found in muskoxen might well yield benefits for mankind. The ten animals now held captive at Fairbanks and the 175 atUnalakleet, Alaska, provide good samples for these studies.