Elephants, rhinoceroses, giraffes, and hippopotamuses – celebrated large animals of the African savanna – are among the Birmingham Zoo’s most cherished residents. These animals are so big that biologists refer to them as “megafauna.”
Birmingham once had its own menagerie of native megafauna. Just a few thousand years ago – not millions – the Southeast was brimming with animals that scientists refer to as the Pleistocene megafauna. The Pleistocene (2.6 million – 11,700 years ago) was a period of ice ages and intervening warm periods. During the most recent ice age, glaciers over a mile thick covered North America to a point just 300 miles north of Birmingham. During this time, many of North America’s animal and plant species were forced into the southeastern US. These included megafauna that had evolved during the millions of years following the extinction of the dinosaurs 65.5 million years ago.
During the Pleistocene, the southeastern climate was cooler and drier than it is now. Forests were restricted to areas protected from the cold such as river valleys and sheltered mountain slopes. Woodlands – open landscapes with scattered trees – and grasslands would have prevailed elsewhere.
Now, imagine this former Birmingham landscape with family groups of huge, elephant-like mammoths and mastodons; large herds of bison, camels, and horses (several species of each); giant ground sloths; and massive armadillo-like glyptodonts. These herbivorous animals were common and likely drank from the many natural springs in the valleys of Birmingham. These herds were prey to a fierce set of large carnivores including the American Lion, Sabre-toothed Cat, Jaguar, and Dire Wolf. It’s exciting to imagine how our Birmingham neighborhoods were home to these animals just a few thousand years ago.
So, what happened to our native megafauna? For a long time, paleontologists – scientists who study ancient life – believed that the warming of the planet after the Pleistocene caused the extinction of these species. However, this wasn’t a good explanation because the megafauna survived periods between ice ages that were just as warm as today’s climate.
In recent decades scientists have uncovered a more likely explanation. An abundance of large spear points and bones with butchery marks have been found throughout North America that date back to the time the megafauna disappeared. It’s now well-accepted that the continent’s first peoples hunted these species to extinction. Imagine if these species survived and were represented in our zoos today!
– Scot Duncan