How It Works
©Brian Regal - Reconstruction of Sthenurus stirlingi, a giant kangaroo from the Sthenurinae family

Giant kangaroos were too heavy to hop

©Brian Regal - Reconstruction of Sthenurus stirlingi, a giant kangaroo from the Sthenurinae family

A new study, published in the journal Plos One, has revealed that extinct kangaroos were up to three times larger than the size they are today and walked on two feet instead of hopping around.

©Brian Regal - Reconstruction of Sthenurus stirlingi, a giant kangaroo from the Sthenurinae family
©Brian Regal – Reconstruction of Sthenurus stirlingi, a giant kangaroo from the Sthenurinae family

The Sthenurine family of kangaroos, which existed in Australia up until around 30,000 years ago, ranged in size, but the largest, the Procoptodon goliah, had an estimated body mass of 240 kilograms (529 pounds).

This called into the question their ability to hop and so a comparison of living and extinct kangaroo skeletons was conducted. It was discovered that these giant kangaroos put their weight on one leg at a time, as their large hip, knee and ankle joints made it impossible for them to hop quickly. They would also support some of their weight on their tail, using it as a fifth limb.

Sthenurine kangaroos can also be distinguished by their short faces, the loss of a fifth digit on their feet, and the ability to browse for food with specialised arms and hands, instead of using their mouths.

To discover more fascinating facts about the natural world, including a guide to the smartest animals on the planet, pick up the latest issue of How It Works magazine.