Scientists have discovered when the kangaroo learned to jump – and that's much earlier than previously thought.
According to new fossils, the origin of the famous kangaroo walk dates back 20 million years.
Live kangaroos are the only large mammal that uses jumps on two legs as their primary form of propulsion.
The extinct cousins of modern kangaroos could also jump, according to a study of their fossilized legs, as well as moving on four legs and climbing trees.
The rare kangaroo fossils were found at Riversleigh in the northwestern Queensland of Australia.
The site is a treasure trove of animal acids, including marsupials, bats, lizards, snakes, crocodiles and birds.
"It's one of the few snapshots we have of the development of marsupials in Australasia for a long time," says researcher Dr. Benjamin Kear from Uppsala University in Sweden.
Kangaroos can quickly cover large distances using their characteristic gait, which is most effective in open habitats such as deserts and grasslands.
The long-term view has been that the animals developed the ability to jump to take advantage of a change in climate, causing dry conditions and the spread of grassland.
But the research, published in the journal Royal Society Open Science, suggests that history is not that simple.
Geometric modeling shows that the old extinct cousins of modern kangaroos could use the same range as living kangaroos.
Evidence, researchers say, kangaroos have had the ability to jump for millions of years.
"It all points to a highly successful animal that is perfectly adapted to its environment and a wide range of habitats and ecosystems, and that is why kangaroos are so successful today," said Dr. Kear.
"It's one of the most biologically nice and wonderful animals you'll probably find."