The Scenario

This scene depicts a landscape about 32 million years ago, in what is now the northern Great Plains at Badlands National Monument, South Dakota. The flood plain of one of many shallow streams in the area passes southeast from the Black Hills through a terrain of low relief. The forest, primarily mixed deciduous trees and conifers, is confined to the vicinity of the stream and nearby floodplain. Hoplophoneus, a saber-tooth carnivore, uses the the cover provided by the brush to stalk a group of unsuspecting early horses, as Archaeotherium, a very distant relative of pigs, keeps a wary eye on the predator.

The Environment

Away from the streams more open areas supported an association of low trees, shrubs, and perhaps some grasses. Rainfall and temperature were seasonally driven. The winters were cooler than during the Eocene; however, temperatures did not drop below freezing for any extended period of time. Alligators still lived in the streams. The summers were warm, with long dry periods. The range of temperatures was narrower than it had previously been in the interior of North America, and much narrower than in this same area today.