Giant rhino ancestors

What it lacked in weaponry the Paraceratherium made up for in sheer size

(Image credit: Tim Bertelink)

Appearing over the horizon or emerging from a patch of trees, Paraceratherium would be an intimidating and somewhat confusing sight to a modern observer: with the height of a dinosaur and the leathery skin of an elephant, it wouldn’t be immediately apparent what these creatures were.

Paraceratherium, scientists now know, was a genus of giant rhino. The group contained towering beasts standing almost five metres tall at the shoulder and potentially weighing 20,000 kilograms. Its members lived across Eurasia during the Oligocene epoch, between 34 and 23 million years ago, and were so far back in the branches of the rhino family tree that they predate the evolution of the facial horn.

Paraceratherium’s exact height isn’t agreed on because the fossils that form our knowledge of the genus are incomplete, but with its estimated size it’s a strong contender for the title of largest land mammal ever. While rhinos today are more compact, Paraceratherium’s legs and neck were relatively long. This impressive body allowed the rhinos to browse tall trees and navigate huge ranges in search of food and mates. To grab hold of foliage, it had a muscular top lip or perhaps even a proboscis like a tapir. Unlike their solitary modern relatives, it’s thought that females and their calves travelled and lived together in small herds.

Despite its size, Paraceratherium was not invincible. Bite marks on fossils suggest that some young and ill animals fell victim to enormous crocodiles, and the entire genus went extinct after about 11 million years on Earth. Elephant-like animals emerging on Eurasia could have reduced the food available to the rhinos by destroying areas of forest, and large predators moving north from Africa may have been able to prey on Paraceratherium calves. The cause of their extinction is unknown, but it’s likely that several factors contributed to the downfall of this graceful giant.

Large but little-known

Relatively little is known about Paraceratherium. The first fossils now recognised as belonging to the genus were collected in Balochistan (modern-day Pakistan) in 1907–1908 by a British geologist. Other fossils began to turn up across Asia but political unrest and global conflict meant that collaboration on research into an extinct rhino genus wasn’t exactly a priority, so discoveries were published in local languages and not shared. 

The correct taxonomy of members of Paraceratherium and their close relatives is still debated, and the fact that a complete skeleton is yet to be discovered means scientists continue to argue about what exactly these prehistoric rhinos would have looked like.

This article was originally published in How It Works issue 120, written by Vicky Williams

For more science and technology articles, pick up the latest copy of How It Works from all good retailers or from our website now. If you have a tablet or smartphone, you can also download the digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, subscribe today!