November in North America

It is possible that if you are from North America you are aware of the trend in the last 20 or so years to take back holidays celebrating European domination of the native populations of this continent. I remember personally seeing protests at Thanksgiving parades in Plymouth and more and more states appear to be dropping Columbus Day as an official holiday or at least renaming it. Given that the United States of America observes a Thanksgiving event in this month, the same holiday as the protests just mentioned for anyone not following U. S. holidays, I thought it might be interesting to look at the fossil history of some of the groups of animals that have been of special importance to the native cultures that once spread across this continent and that we have, to a significant degree, lost over the past 400 years. This is a look into how the animals that became important to the peoples of North America became the animals that they are now and what their fossil history, regardless of how recent those are, reveals about their evolution. I know these are not dinosaurs, but life on Earth is complex and filled with a lot more than dinosaurs, so hold on for the ride, or take a break and come back to us in December. The first animal that we will look at this month is the America Bison.

The American Bison (Bison bison) has a long history that, like a significant number of animals, starts on another continent; there is an extant European Bison (Bison bonasus) distantly related to and far more rare than the American Bison. The fossils we are going to discuss are the members of the family that arrived or thrived in North America prior to the appearance of what we would recognizably call the American Bison. Three extinct species of the genus Bison were endemic to North America prior to the appearance of Bison bison, the American Bison, in the fossil record. These species were, in order, B. latifrons, B. occidentalis, and B. antiquus. They range from approximately 240,000 years ago when B. latifrons is thought to have initially crossed the Bering Land Bridge into North America to approximately 5,000 years ago when B. antiquus appears to have gone extinct. The three species are not identical and B. latifrons is actually quite impressive, measuring in at 2.5 meters (8.2 ft) and estimated to have tipped the scales at 2,000 kilograms (4,400 lb); that is almost as tall as a modern Asian Elephant. The horns of B. latifrons measured approximately 213 centimeters (84 in) from one tip to the other. Bison bison measures in with horns approximately 66 centimeters (26 in) from tip to tip. Bison occidentalis is less well-known, but it is smaller than B. latifrons and its horns, also much smaller, pointed toward the rear of its skull, rather than the front. Bison antiquus was nearly as tall at 2.27 m (7.5 ft) but much lighter at 1,588 kg (3500 lb) and with horns noticeably smaller, though pointing forward, that measured approximately 1 m (3 ft) wide.

Photo from North Dakota Department of Mineral Resources. B. latifrons exhibit at the North Dakota Heritage Center