Did You Hear About The Giant Kangaroos?

A new study reveals three unique species of giant fossil kangaroos; they are as bizarre as they are diverse.

I’ve always been fascinated by kangaroos. I mean, who isn’t? While doing my PhD in Australia, I had the chance to study these incredible animals up close, and I’ve been hooked ever since. And well, it wasn’t just the study part. I still remember camping in Jervis Bay, a beautiful beach location a few hours south of Sydney, and waking up to a sea of kangaroos sleeping all around us. I promise I’m not lying when I say I had to solve a labyrinth of sleepy marsupials to make it to the bathroom.

So, you can imagine my excitement when I heard about a groundbreaking new study that dives deep into the world of GIANT fossil kangaroos. And by giant, we mean twice as big as their biggest modern counterparts (red kangaroos). Those animals were scary in their modern size.

The research comes from Flinders University (some of my good friends graduated there) and describes not one, not two, but THREE new species of the extinct Protemnodon genus, bringing fresh insights into how these ancient giants lived, hopped, and adapted.

Protemnodon is an extinct genus of giant kangaroo that roamed Australia and New Guinea between 5 million and 40,000 years ago. This new research, published in Megataxa, sheds light on their unique characteristics, revealing a surprising range of sizes, shapes, and behaviors.

What’s fascinating is that these new species of Protemnodon aren’t just big — they’re also diverse in many ways. For example, let’s look at Protemnodon viator, a colossal kangaroo that could weigh up to 170 kg — about double the size of the biggest red kangaroo we know today. It’s not just their size that sets them apart. Protemnodon viator had also long limbs and could hop with remarkable speed and efficiency, which suggests that it was well-suited to its arid central Australian habitat. The name “viator” means “traveler” or “wayfarer,” which couldn’t fit it better.

Another newly described species, Protemnodon mamkurra, had a different lifestyle and niche. This one was big, robust, and probably not very fast, possibly hopping only when absolutely necessary. Its fossils were found in southeastern South Australia, and the name “mamkurra” comes from the Boandik people, meaning “great kangaroo.” It’s quite fitting for a creature that might have moved with a slow, steady grace.

Then there’s Protemnodon dawsonae. This one remains a bit of a mystery because we don’t have as many fossils to work with. But this species was likely a mid-speed hopper, something like a swamp wallaby. Its fossils come mostly from the Wellington Caves in New South Wales, and it’s named in honor of Dr. Lyndall Dawson, an Australian paleontologist who made significant contributions to the study of kangaroo systematics.

So, how did this study come together? Dr. Kerr and his team visited 14 museums across four countries to study every Protemnodon fossil they could find. They took photos, performed 3D scans, and countless measurements to create a clearer picture of these fossil kangaroos. The volume of data they collected — more than 800 specimens — is impressive. I remember collecting the same type of data, and it would take me a whole week to process 10 to 15 specimens. So, hats off Dr. Kerr et al.

However, one of the most intriguing aspects of this study is how it challenges previous assumptions about these kangaroos. It was once thought that Protemnodon species were mostly quadrupedal, but this research shows that only a few might have moved like that. Instead, we see a range of hopping styles, from slow and steady to quick and agile. This diversity suggests these kangaroos adapted to various environments, from arid central Australia to the lush forests of Tasmania and New Guinea. If that’s not an evolutionary success, I don’t know what is.

The big question now is why these species disappeared about 40,000 years ago. Despite their varied adaptations and wide-ranging habitats, they all eventually went extinct. The researchers suggest that further studies on Protemnodon could help uncover more about their extinction and why related species like wallaroos and gray kangaroos survived.

This study sharpens the world of these ancient species and opens the door to new questions and discoveries. As someone who’s been captivated by kangaroos since my time in Australia (ok, probably earlier than that), I’m thrilled to see such a comprehensive study on these iconic animals. It’s a reminder that there’s always more to learn, even about the most familiar animals.