We know and love kangaroos as graceful hoppers. But not all of the charismatic marsupials were able to bound across Australia's grasslands. During the last Ice Age, over 30,000 years ago, there were immense, rabbit-faced kangaroos that were so big that they had to take it one step at a time.
Known as sthenurine kangaroos to paleontologists, these fossil mammals aren't new to science. The British anatomist Richard Owen named two of the giants - Sthenurus and Procoptodon - in 1873. But ever since their discovery, scientists have been perplexed by the peculiar anatomy of the long-lost marsupials.
For one thing, the giant ‘roos had strange feet. Each foot was really a big, single toe that ended in a hoof-like claw. They also had stockier skeletons for their size, with shorter tails than is typical for kangaroos. And in addition to rounded, rabbit-like faces, kangaroos like Sthenurus had evolved specialized arms and shoulders that allowed them to reach above their heads to pull down succulent leaves. In lifestyle, at least, they were less like modern kangaroos and more like marsupial equivalent of giant ground sloths.