why birds survive dinosaur extinction

The story of the disappearance of dinosaurs is a famous one. Less familiar is the tale of the dinosaurs that were left behind.

What is it about birds that allowed them to survive when all other dinosaurs died out? Watch our animation.

By the start of the Jurassic Period, 201 million years ago, dinosaurs had become the global superstars of the animal kingdom.

There were lots of them – and lots of different species – and they held the top carnivore and top herbivore spots in food chains.

The end of dinosaurs’ rule: the Cretaceous extinction

The dinosaur era ended abruptly after more than 140 million years when a massive asteroid strike and massive volcanic eruptions drastically altered the environment. Most dinosaurs went extinct. Only birds remained.

Birds underwent numerous evolutionary changes over the ensuing 66 million years, allowing them to flourish in a wide range of environments. Today there are at least 11,000 bird species.

But how come birds survived, given their close kinship with the extinct dinosaurs?

Their small size, their ability to eat a wide variety of foods, and their ability to fly are likely contributing factors to the answer.

Watch the animation to find out more.

Discover what researchers at the Museum are learning about the appearance, physiology, and behavior of dinosaurs.

The goal is to locate additional fossils from the Paleocene, the period immediately following one of the greatest mass extinctions in history, in order to gain a better understanding of how birds survived and subsisted in a world slowly returning from this devastating event. Bird fossils from the Cretaceous to Eocene transition zone are fragmentary and difficult to locate, but paleontologists have some excellent examples of fossilized birds from the Eocene, a period that began roughly 10 million years after the catastrophe. These are the bones that may reveal new secrets.

Paleontologist Derek Larson of the Royal BC Museum says, “There has been a lot of discussion about what enabled modern-type birds to survive the K-Pg extinction while other bird groups, non-avian dinosaurs, and even pterosaurs perished.” There was a wide variety of birds and reptiles that resembled birds at the end of the Cretaceous. However, only the beaked birds made it out of these groups alive. The major events were set in motion well in advance of the asteroid strike, giving birds a fortunate break due to the accidents of evolution.

The way that beaks form during development may have aided in the evolutionary shift in those birds that started to lose their teeth in favor of beaks. According to anatomist Abigail Tucker of King’s College London, “changes to the skull and face as the beak became more complex may have moved developing tissues around, changing how they interact in the embryo, and resulted in the loss of tooth formation.”

“Everything that makes birds, birds, was already in place well before the mass extinction,” anatomist Ryan Felice of University College London states.

By the end of the Cretaceous, beaked birds were already eating a much more varied diet than their toothed relatives. These birds weren’t specialized on insects or other animal food, and so they were able to pluck up hard food items like seeds and nuts. And in the aftermath of the extinction, when animal life was severely cut back, those hard, persistent little morsels got beaked birds through the hard times. Beaked birds were able to feed on the seeds of the destroyed forests and wait out the decades until vegetation began to return.

The beginning of birds

The oldest bird fossils are about 150 million years old. These extinct birds shared many characteristics with small, feathered dinosaurs. Their mouths still contained sharp teeth. But over time, birds lost their teeth and evolved beaks. Can you imagine coming face-to-face with a toothy pigeon?.