Why did birds survive while dinosaurs became extinct?

After the asteroid hit Earth 66 million years ago, some toothless birds may have survived thanks to their ability to forage.

Birds evolved from dinosaurs about 160 million years ago. In fact, birds and dinosaurs lived together for about 100 million years. Birds originated from a group of dinosaurs called Dromaeosaurs , or 'running lizards,' a family of feathered theropod dinosaurs.

Dinosaurs once lived alongside birds, but became extinct when an asteroid hit Earth. (Photo: Corey Ford/Stocktrek Images).

66 million years ago, when an asteroid slammed into Earth in the waters off what is now Mexico, the dinosaurs were wiped out. However, some species of birds survived.

Scientists who study bird evolution are trying to figure out why birds didn't go extinct. They piece together clues like fossils and other evidence of life on Earth in ancient times to come up with a few theories about why birds survived, though no definitive answers are available.

Birds today do not have teeth. Instead, they have beaks of different shapes and sizes to eat. During the time of the dinosaurs, some birds still had teeth, while others did not.

After the asteroid hit Earth, all toothed birds became extinct, but many toothless species survived. Some scientists believe that their toothless nature helped them survive.

Fossils of ancient toothless birds show that they were more likely to eat plant-based foods, especially seeds and fruits. This means that, compared to birds with teeth, they were less dependent on eating other animals.

Ichthyornis dispar, an ancient toothed seabird that lived during the Late Cretaceous (about 100 million - 66 million years ago) in North America. (Photo: Michael Hanson/Bhart-Anjan S. Bhullar)

Some scientists believe that this difference in diet came to great advantage after the asteroid hit, which immediately triggered tsunamis and massive earthquakes. The massive heat pulse from the impact sparked massive wildfires near the asteroid's landing site. In the months that followed, a large amount of dust filled the atmosphere around Earth, blocking out the sun and leaving plants with little light to grow.

For herbivores, food became extremely scarce. Many species became extinct, causing problems for hunters. Many animals were wiped out and plants had difficulty getting enough sunlight, so food became very difficult to find. But if an animal had the ability to peck at the ground and find buried seeds or nuts to eat, it could survive.

Of course, there are other factors that may have contributed to toothless birds surviving while their toothed 'siblings' perished, including luck. For now, that remains a mystery that has yet to be fully solved.

Scientists will come up with an idea or hypothesis based on their existing knowledge and information. They then test the idea by conducting experiments or collecting more evidence. This information will either support or disprove the original idea. So scientists are willing to revise the story of how birds survived and dinosaurs went extinct as they gather more information from rocks, fossils, and ancient DNA.