Giant ice age kangaroos had massive cheekbones for crushing bites

By Ruby Prosser Scully

© N. Tamura

Extinct massive kangaroos had skulls built to ship the highly effective crunch wanted to eat significant food, equivalent to branches and stems. This may perchance perchance perchance additionally have allowed them to continue to exist prolonged stretches of time when reasonably about a food turn out to be once scarce.

Immediate-faced kangaroos lived in Australia at some stage within the final ice age and are known for their short snouts, mammoth jaws and teeth, and heavily built skulls.

D. Rex Mitchell at the University of Current England, Australia, created a digital mannequin of the cranium of one kind of short-faced kangaroo, the 120-kilogram Simosthenurus occidentalis, and analysed the results of reasonably about a biting behaviour.

He came across that the mammoth kangaroo had teeth so shut to the jaw joints that, if its cheek muscle groups were proportionate to the tree-kangaroo, a living relative, then the possibilities of its jaw dislocating were excessive.

“But what I realized turn out to be once that this species has absurdly mammoth cheek bones,” says Mitchell. So when he scaled up the dimension of the cheek muscle groups to compare the dimension of the cheekbones, the digital mannequin confirmed that the dangers of the jaw dislocating dropped considerably.

Big pandas have in an analogous vogue mammoth cheekbones that toughen the identical mammoth, stabilising muscle groups. This implies the kangaroo may perchance perchance additionally have extinct their premolars to crunch down on significant plant discipline cloth, significant worship pandas eat bamboo, says Mitchell.

Alternatively, it is generally imaginable that the kangaroos held significant branches of their teeth and pulled them down to interrupt them.

The digital mannequin suggests the mammoth kangaroo may perchance perchance well well have eaten tougher vegetation than any at demonstrate living Australian herbivores can, says Mitchell.

S. occidentalis is believed to have survived till spherical 42,000 years within the past, which diagram it perchance lived alongside humans for spherical 20,000 years.

Journal reference: PLOS ONE, DOI: 10.1371/journal.pone.0221287