Appetite for seeds helped birds outlive dinosaurs


Some bird-like dinosaurs managed to survive the dino-killing asteroid. A study suggests having a toothless beak may have helped them push through. Jake Port reports.


Artist's impression of a number of bird-like dinosaurs at the end of the Cretaceous. Middle ground and background: two different dromaeosaurid species hunting vertebrate prey (a lizard and a toothed bird). Foreground: hypothetical toothless bird closely related to the earliest modern birds. – Danielle Dufault

Most dinosaurs met their demise when an asteroid crashed into Earth, but birds managed to pull through and even thrive. New research suggests their secret to survival success was their appetite for seeds.

A trio of paleontologists in Canada, led by the University of Toronto’s Derek Larson, suggest the sudden extinction of toothed birds at the end of the Cretaceous may have been because they couldn’t eat seeds, while their toothless, seed-eating counterparts flourished.

More than 65 million years ago, toothed and toothless bird-like dinosaurs lived alongside. Some ate meat, others ate plants and some ate both.

But when the asteroid hit, wiping out most species on Earth, “modern [toothless] birds managed to survive the extinction,” Larson says. “The question is: why did that difference occur when these groups were so similar?”

So he and his colleagues looked at 188 current bird species and traced them to a common ancestor.

That common ancestor, they found, was a bird-like dinosaur with a toothless beak, and consumed seeds as part of its diet. And when the asteroid hit, kicking up a sun-blocking layer of dust, those toothless species could keep eating their seedy meals.

Flowering plants (angiosperms), which produce seeds, were abundant at the end of the Cretaceous period. Those seeds would have been one of the few food sources left, even with the acid rain and sweeping fires that followed the impact.

But species reliant on leaves and fruit suffered, as plants were unable to photosynthesise. Toothed bird-like dinosaurs that mostly ate meat, but didn’t have seed-cracking abilities, then had less prey. And for them, the asteroid spelled the end.

The study was published in Current Biology.

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  1. http://www.cell.com/current-biology/fulltext/S0960-9822(16)30249-4
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