BEIJING, China — A giant rhino fossil unearthed in China could reveal the largest land mammal that ever lived, according to a new study. Researchers say the colossal creature was likely more than 26 feet long, over 16 feet tall, and weighed 24 tons.
This makes it four times the size of an African elephant, the biggest animal that currently walks the Earth. Study authors believe the hornless herbivore roamed through Asia 26.5 million years ago, browsing the forests for leaves, soft plants, and shrubs.
The fossil resembles an overgrown tapir and scientists have named it Paraceratherium linxiaense. The study finds the bizarre animal had a slender skull, short trunk, and an unusually long and muscular neck.
Piecing the giant rhino back together
The discovery sheds fresh light on how the friendly giants migrated across continents. Along the way, they likely faced prehistoric hyenas, giant crocodiles, and endured the frigid wilderness of the Ice Age.
“It had a body weight of 24 tons, similar to the total weight of four African elephant or eight white rhinos,” says lead author Professor Tao Deng of the Chinese Academy of Sciences in a statement to SWNS.
“It was five meters (16.4ft) high at the shoulders and 8 meters (26.25ft) long. The giant rhino’s long legs were good for running. Its head can reach a height of 7 meters (23ft) to browse leaves of tree tops. Its prehensile nose trunk was extremely useful to wrap around branches – allowing the sharp front teeth to strip off the leaves. Its tusk-like incisors are primarily used to break twigs and strip bark, as well as to bend higher branches.”
The skull and legs are longer than all reported land mammals. Researchers believe the animal was most likely suited to open woodlands under humid or arid conditions. Paraceratherium was identified from a perfectly preserved skull, jaw, and atlas – the first cervical vertebra of the spine that supports the head.
‘Largest land mammal’ has a mysterious origin story
A team discovered the fossilized remains at a prehistoric animal graveyard in Gansu, north western China. Giant rhino specimens are scarce and most fossils are only fragments. These are among the best-preserved and will help fill an important branch in the beast’s family tree.
“It is one of the largest land mammals that ever lived. The giant rhino has primarily been found in Asia. But its evolutionary relationships remain unclear,” Prof. Deng explains. “This animal has distinct characters – a slender skull with a short nose trunk and long neck, and a deeper nasal cavity than other giant rhino species.”
Paraceratherium, which study authors describe in the journal Communications Biology, is closely related to the giant rhinos of Pakistan.
“It raises the possibility the giant rhino could have passed through the Tibetan region before it became the elevated plateau it is today,” Deng continues. “From there, it may have reached the Indian-Pakistani subcontinent in the Oligocene epoch between 34 and 23 millions years ago where other giant rhino specimens have been found.”
The giant rhino is one of the most iconic Ice Age beasts, wiped out by climate change, disease, and human hunting. However, its origins are still a mystery.
“The Tibetan region likely hosted some areas with low elevation, possibly under 6,500ft during Oligocene,” the lead author says. “The lineage of giant rhinos could have dispersed freely along the eastern coast of the Tethys Ocean and perhaps through some lowlands of this region.”
New fossil is providing clues about ancient geography
Scientists note that the rock that forms the Himalayas was once submerged in the ancient sea. Giant rhino remains have also been discovered in Eastern Europe, but researchers believe they mainly lived in China, Mongolia, Kazakhstan, and Pakistan.
“During the Oligocene, dispersal for the giant rhino from the Mongolian Plateau to South Asia could have been along the eastern coast of the Tethys like other mammals, such as anthracotheres and ruminants,” Prof. Deng adds.
The discovery adds to evidence the Tibetan region was not yet the elevated plateau it is today, without the mountainous terrain which would to deter the giant rhino and other great mammals from living there. This possibility is supported by other evidence. Fish and plant fossils dating back to the same period from central Tibet display tropical characteristics, indicating a lower elevation.
“Through to the late Oligocene, the evolution and dispersal of the giant rhino demonstrate Tibet, as a plateau, did not exist and was not yet a barrier to the largest land mammals,” Prof. Deng concludes.
Scientists speculate that the Paraceratherium would have been majestic, even in comparison to other amazing mammals of Eurasia living between 20 and 35 million years ago. Its vertical reach enables it to eat food at the top of the canopy, unlike the modern elephant’s method of extending a flexible trunk.
So where did all the giant rhinos go?
The arrival of a different kind of herbivore might have triggered ecological changes that helped drive the rhinos to extinction. At the time, tropical forests were shrinking and grassy savannahs were spreading. The lush grasslands suited giant rhinos down to the ground.
Rhinos belong to a group of animals called perissodactyls. They have hooves and an odd number of toes on their rear feet. Scientists believe they first appeared 55 million years ago in India, which at the time was not attached to Asia.
Perissodactyls were the ancestors of today’s rhinos as well as all modern horses, zebras, and tapirs. It is not clear why Oligocene rhinos got so big. It may have been a way of coping with the more open habitat. What’s more, despite being so large, Paraceratherium wasn’t safe from predators. It and other huge prehistoric rhinos were hunted by gigantic crocodiles and “dog-bears” called Hemicyon.
SWNS writer Mark Waghorn contributed to this report.