Giant kangaroo twice the size of a human roamed Australia 5 million years ago, study shows
Australia may be known for its unusual and dangerous wildlife, but five million years ago scientists said things would have been even stranger.
Giant kangaroos – some more than twice the size of a human – roamed the land for millions of years, a new study shows.
Researchers from Flinders University have discovered three new species of giant fossil kangaroos that spread from the deserts of Australia to the jungles of New Guinea.
The largest species, Protenmodon viator, weighed up to 170 kg (375 lbs) and is thought to have traveled across central Australia on its long limbs.
Dr. Isaac Kerr, lead author of the study, said: ‘Living kangaroos are already such remarkable animals, so it’s amazing to think what these peculiar giant kangaroos could have been up to.’
Scientists have discovered that giant kangaroos twice the size of a human are believed to have roamed Australia’s arid heartland five million years ago
Scientists have discovered three new species of giant kangaroo that lived in Australia five million years ago. This artist’s impression shows two of these species, Protemnodon anak (top) and Protemnodon tumbuna (bottom)
This prehistoric rose would have looked a lot like a modern gray kangaroo, albeit stockier and more muscular.
The researchers think they originated about five million years ago and went extinct about 40,000 years ago.
The smallest of these ancient kangaroos is said to have weighed about 50kg, about the same size as a modern Eastern Grey.
The largest species is said to be about twice the size of an adult male red kangaroo, which can grow up to 6 feet (1.8 meters) tall.
Although the three new species are all members of the same family, it would be unusual for them all to have led very different lives.
The fossil record shows that these closely related species were specially adapted to their unique environments and would even have jumped differently.
Dr. Kerr said: ‘The different species of Protemnodon are now known to have inhabited a wide range of habitats, from arid central Australia to the forested, high rainfall mountains of Tasmania and New Guinea.’
Protemnodon Viator (pictured) is thought to have been the largest of the ancient kangaroos, weighing as much as 170 kg (375 lbs). This nearly complete skeleton shows how long its legs would have been
The ancient kangaroos would have been twice the size of an adult male red kangaroo (pictured), which at 1.8 meters tall can be taller than some humans
The giant Protemnodon viator takes its name from the Latin for “traveler” because of its long legs that allowed it to jump quickly and efficiently.
However, of the four Protemnodon now known to science, only one was truly bipedal.
The researchers say the others would have moved like a modern Quokka, mostly on four legs and only occasionally hopping.
Dr. Kerr says: ‘It was a large, robust, thick-boned kangaroo and probably quite slow and inefficient.
“Maybe he jumped only rarely, maybe only when he was startled.”
Protemnodon dowsonae, the third new species, is thought to have been a medium-sized hopper – although scarce fossils make this animal’s life more of a mystery.
Not all ancient kangaroos would have jumped; the scientists say most would have jumped on all fours like a quokka (photo)
The first specimens of Protemnodon species were discovered as early as 1875 by Sir Richard Owen, the Victorian scientist who coined the term dinosaur.
By looking at fossil teeth, Owen concluded that there were six different species of Protemnodon.
However, only one of Owen’s identified species, Protemnodon anak, is still scientifically recognized.
The difficulty in assessing these ancient kangaroos stems from the fact that their bones are often found isolated, making complete skeletons extremely rare.
This only changed after a series of complete fossils were discovered in Lake Callanbonna in South Australia in 2013, 1018 and 2019.
Dr. Isaac Kerr, lead author of the study (pictured) analyzed more than 800 different kangaroo fossils in four countries to identify the new species
Protemnodon fossils are common, but it is rare to find a complete skeleton. This image shows two volunteers unearthing the largest known kangaroo fossil at Lake Callabonna, Australia
To identify the new species, Dr. Kerr to 14 museums in four countries, where he photographed and scanned more than 800 specimens.
By assessing “just about every piece of Protemnodon there is,” Dr. Kerr and his colleagues identify the distinguishing features and adaptations of the new species.
The researchers hope this study will help future paleontologists study ancient kangaroos more easily.
Their discoveries could even help explain why these giant species became extinct while the gray and red kangaroo continued to thrive.
Professor Gavin Prideaux, co-author of the study, added: ‘The fossils of this genus are widespread and regularly found, but more often than not you can’t be sure which species you are looking at.
‘This study can help researchers gain more confidence when working with Protemnodon.’