A modern female musk ox.
A modern female musk ox, named Eider, in Palmer, Alaska.

Today, surviving wild musk oxen (Ovibos moschatus) are restricted to northern latitudes, living in places like Arctic Canada, Greenland, Alaska, Scandinavia and Siberia. During the last Ice Age, however, musk oxen and their close relatives were able to range over a much larger portion of the globe. In North America, fossil evidence suggests extinct species of musk ox inhabited North America from Alaska down to Mexico.

Texas is a state famous for fossil-finds, like the dinosaur footprints at Dinosaur Vallery State Park or the in situ mammoth skeletons at Waco Mammoth National Monument.

Back in March 2020, two scientists, Dale Winkler, Ph.D., from Southern Methodist University and Alisa Winkler, Ph.D., from the University of Texas Southwestern, reported on two amazing fossil finds from Texas in a publication titled New records of Late Pleistocene ungulates (Bootherium and Tapirus) from North Central Texas.

Generally, Pleistocene mammal fossils found in Texas come from mammoths, mastodons and extinct species of bison and horse. The discovery of fossils of Bootherium bombifrons (the extinct “woodland musk ox”, a relative of modern Ovibos musk oxen) and Tapirus veroensis (an extinct species of tapir) show that an exciting diversity of mammalian wildlife existed during the end of the Ice Age.

The Winklers identified the tapir on the basis of a partial left manidble (lower jaw) with teeth that was found in Denton County, Texas (Denton is better known as the home of pop-punk band Bowling for Soup). Modern tapirs are found in Central and South America and parts of Asia.

The Bootherium fossil consists of a mostly complete cranium (skull minus the jaw), including the bony horn cores and maxillary (upper) teeth. The Bootherium skull was found in Lamar County. Detailed photographs of the fossil cranium are available in the Winklers’ publication.

The Winklers’ dated the fossil to the “Latest Pleistocene” based on other known animal fossils from the same geologic formation, though the Late Pleistocene encompasses a vast period of time from 129,000 to 11,700 years ago. The Winklers estimate their Bootherium fossil to be from “21,000 – 24,000 years BP[before present] or possibly as much as 75,000 years BP.”

Three other Bootherium crania were found in Texas prior to the Winklers’ fossil. The rarity of Texan musk ox fossils makes this find all the more important. The Winklers’ note that:

“Although the remains of Bootherium are not uncommon from some parts of North America, for example the midwestern United States, specimens from the south, including Texas, are rare.”

Elsewhere in North America, Bootherium is believed to have survived until about 11,000 years ago, corresponding with the enivonmental changes that marked the final end of the Ice Age and the beginning of the Holocene Epoch.

The presence of Bootherium fossils from North Central Texas also opens questions about human-musk ox interaction. Texas has a number of archaeological sites dating back to the late Pleistocene, including the Aubry Clovis Site in Denton County - dating back 11,500 years ago - and the Gault Site - possibly older than 13,000 years.

Did Clovis (or pre-Clovis) humans in Texas encounter Bootherium?