Humans, not climate change, may have wiped out Australia’s giant kangaroos

The demise of astir of Australia’s kangaroo type by 40,000 years agone whitethorn person had little to do pinch climate-caused dietary pressures and much to do pinch quality hunters.

Dental analyses of ancient kangaroos uncover they weren’t specified picky eaters arsenic erstwhile thought, researchers study successful nan Jan. 10 Science. Instead, erstwhile it came to climate-related changes successful nutrient availability, nan animals mightiness person rolled pinch nan punches, nan scientists suggest.

Between 65,000 and 40,000 years ago, much than 90 percent of Australia’s ample animal type went extinct. Over half were kangaroos. The superior suspects down these extinctions were thought to beryllium human hunters, who had arrived sometime betwixt 70,000 and 50,000 years ago, and rapid changes successful nan climate, which whitethorn person dramatically reduced nan animals’ dietary options.

But to paleontologist Samuel Arman of nan Museum and Art Gallery of nan Northern Territory successful Alice Springs, Australia, and colleagues, nan ambiance presumption didn’t make a batch of sense, astatine slightest erstwhile it came to kangaroos. The animals had weathered melodramatic ambiance shifts before.

Australia’s kangaroos evolved betwixt 20 cardinal and 15 cardinal years ago, erstwhile nan continent was a lush rainforest. By 5 cardinal years ago, nan land had dried retired — yet nan kangaroos thrived, diversifying into caller type and occupying galore biology niches that encompassed a wide assortment of diets.

To measure nan imaginable domiciled of dietary restrictions, Arman and colleagues analyzed nan teeth of 937 kangaroos, some fossilized and modern, studying mini signs of deterioration and tear that constituent to what nan creatures ate.

Previous studies of fossilized skulls and jaws suggested galore ancient kangaroos consumed a restricted fare of reliable plants, arsenic opposed to nan comparatively supple grasses of modern-day kangaroos. But nan caller dental study of 12 ancient type and 16 modern ones suggests nan long-gone kangaroos were generalists, consuming a assortment of foods that would person helped them past arsenic nan ambiance changed. That, nan researchers say, points to quality hunters arsenic nan much apt superior culprit for nan animals’ demise.

It’s not nan first clip dental microwear analysis has called into question dietary assumptions of ancient creatures — including humans — gleaned from cranial study alone, nan researchers say. That, they add, suggests it’s worthy testing nan teeth of different ample Pleistocene mammals to genuinely understand really specialized their diets were — and whether nonaccomplishment of those diets led to their demise.