Ari Daniel

Sam Arman took a detailed look at the teeth of more than 900 kangaroos from both fossils and modern animals.

Armin, who's a paleontologist at a natural history museum in central Australia, used those scratches to figure out what the ancient kangaroos ate. His answer, a mix of shrubs and grasses, suggesting that a changing climate that wiped out a single group of plants likely wasn't behind the extinctions. Rather, he thinks humans who arrived in Australia around this time had something to do with it.

Armin, who's a paleontologist at a natural history museum in central Australia, used those scratches to figure out what the ancient kangaroos ate. His answer, a mix of shrubs and grasses, suggesting that a changing climate that wiped out a single group of plants likely wasn't behind the extinctions. Rather, he thinks humans who arrived in Australia around this time had something to do with it.

Other paleontologists disagree, citing evidence that climate change did play more of a role. For NPR News, I'm Ari Daniel.

Other paleontologists disagree, citing evidence that climate change did play more of a role. For NPR News, I'm Ari Daniel.