Las Dantas panel at Cerro Azul, La Lindosa (arrow points to proposed giant sloth painting).
Credit: José Iriarte, et al/Royal Society B 2022

Did ancient Americans in the forests of South America see strange prehistoric mammals before they disappeared forever at the end of the Ice Age? Cave paintings discovered in a remote region of Colombia appear to depict giant ground sloths, elephant-like gomphotheres, ancient horses, and a car-sized armadillo relative called a glyptodont. The paintings provide a rare glimpse of a long-lost ecosystem, populated by giant animals known as megafauna, that few people had ever set eyes upon.

The paintings were discovered at Serranía de la Lindosa, a natural rock shelter on the banks of the Guayabero River in central Colombia. Although the cave paintings were known to the Indigenous people of the region, they were inaccessible to scientists due to the remote location and ongoing civil conflict in the area. However, scientists have been able to study the paintings in detail in recent expeditions. The images were created using red ochre, a natural mineral pigment commonly used in cave paintings throughout the world.

The cave paintings show several familiar South American animals, including capybaras and horses. The researchers believe the paintings depict native horses from the region before they became extinct about 10,000 years ago rather than modern horses that were introduced to South America by the Spanish in the 1500’s.

Other figures seem to show strange Ice Age megafauna that became extinct thousands of years ago. One intriguing image depicts a large, stocky animal with elongated forearms next to what appears to be its cub. Researchers believe this image depicts a giant ground sloth, an extinct relative of the modern sloth that was as large as an elephant. The researchers identified other possible Ice Age species in the paintings, including a gomphothere (a relative of modern elephants), a glyptodont, and a bizarre hoofed mammal called Litopterna, which resembled an antelope with a short trunk-like snout.

There is abundant evidence from cave paintings in Europe and Asia that humans coexisted with Ice Age megafauna before they went extinct. However, similar cave paintings are rare in the Americas. No people lived in the Americas before Indigenous people arrived. Most scientists think the first people came to the Americas from Asia at least 15,000 years ago. Many of the animals depicted went extinct soon after the arrival of humans in the region. By about 10,000 years ago, horses, mammoths, gomphotheres, ground sloths, and glyptodonts had disappeared. Scientists continue to debate the role of human hunters in the extinction of Ice Age megafauna in the Americas. Many scientists believe that other factors, such as climate change at the end of the Pleistocene Epoch may have had a larger role in the extinction of these great beasts.

December 5, 2016

Imagine going to the zoo and seeing a horselike rhinoceros the size of a small house. It may sound like a fairy tale monster, but Paraceratherium—break it down: para-cera-therium (par uh sehr uh THIHR ee uhm)—was real and it was the largest land mammal that has ever lived. Paraceratherium, which provided inspiration for the gargantuan AT-AT walkers seen in the Star Wars film and entertainment franchise, reached over 16 feet (5 meters) in height. Its skull alone was over 4 feet (1.2 meters) long.

Watch their step: a Paraceratherium herd feeds on a not-so-small leafy tree. Credit: American Museum of Natural History

A prehistoric relative of the modern rhinoceros, Paraceratherium roamed central Asia between 20 and 30 million years ago. It was about 10 feet (3 meters) taller than modern rhinos, and it had no horn. The giant walker had long legs and a long neck to reach leaves in the treetops. Paraceratherium ate vast amounts of plant matter every day to maintain its massive 15-ton (13.6-metric ton) weight. It was so big that even a newborn calf was too much for many large predators to handle, especially with its massive mother lurking protectively nearby. Males had very thick skulls, which they used on each other as clobbering weapons while competing for mating rights with females. The thunderous stomping and skull-crashing during these combats probably warned other creatures to stay far away.

Scientists suspect that Paraceratherium’s cumbersome size led to its demise. Such a gigantic body requires a lot of food fuel and can easily overheat, which is why most modern mammals tend to be small- to medium-sized. Droughts, food shortages, and heat waves would have left Paraceratherium quite vulnerable. Females gave birth to only one calf every few years, so it would have been difficult for these prehistoric giants to keep their population numbers up during tough times.