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Fossil Musk Oxen in Iowa:
When Were They Here and What did They Eat?

In November, 2000, UI Department of Geoscience Ph. D. candidate Richard Slaughter came to the Museum to collect bone samples from musk ox skulls in the collection.

Two kinds of musk oxen lived in Iowa during the Ice Ages -- the extinct woodland musk ox, Bootherium bombifrons, and the barren ground musk ox, Ovibos moschatus. The latter still survives in the arctic tundra of North America and in Greenland. (Mammal Hall diorama). Slaughter will date the skulls of two woodland musk oxen and three barren ground musk oxen recovered from Ice Age deposits in Iowa. Iowa musk oxen fossils have never been radiocarbon dated before.

The information will help determine how long each species lived in Iowa and whether or not they lived here at the same time.

Slaughter taking a sample from a barren ground musk ox skull collected by UI graduate student Frank Russell in 1894. Assisting Slaughter is Steven Wallace.
Slaughter will also calculate carbon isotope ratios for each specimen. Very little is known about the diet and habitat of the woodland musk ox. The isotope ratios will reveal the proportion of C3, cool-adapted, and C4, warm adapted plants in the animals' diets. Twenty modern barren ground musk oxen skulls will be tested to determine if the diet and habitat of the species has changed since the Ice Age. If no changes are detected, the radiocarbon dates on the fossils will provide adates of exactly when tundra was in Iowa.

This research is supported by a grant from the Iowa Science Foundation.
That Craftsman drill is tipped by a special $200 diamond-coated bit designed to extract the small plug of bone lying behind the skull. A one gram sample will help provide a baseline for the carbon isotope ratio needed to determine the animal's diet.

Slaughter will send the bone samples to the Rafter Radiocarbon Laboratory in Lower Hutt, New Zealand, one of the best radiocarbon dating laboratories in the world. The results should be back in 2-3 months. We will report them here.

Rich's research often takes him into Iowa caves where he searches for the fossil bones of small mammals---indicators, for him, of ancient climates.