Why did birds survive when meteorites wiped out dinosaurs?

About 66 million years ago, a meteorite collided with Earth and led to the extinction of the ornithopod. This collision created a series of terrifying events: tremors, wildfires, acid rain, tsunamis, volcanic eruptions - killing about 80% of all animals. However, some dinosaurs did survive: the birds.

66 million years ago, a meteorite fell to Earth killing about 80% of all animals, including dinosaurs.

However, not all birds have survived, some have perished. Well-preserved ancient bird skulls have helped researchers better understand how birds survived the impact.

The scientists found that the birds that survived were those with larger cerebrum. Still, it's not clear why this region helps birds survive, as it's responsible for so many processes. 'Birds with larger brains can change their behavior fast enough to keep up with environmental changes,' said Chris Torres, a researcher in Chiropractic Medicine at Ohio State University.

Fossils of Ichthyornis.

Bird bones are very perishable and rarely fossilized in good condition, so scientists rarely get a chance to get a good look at the cerebral cortex of ancient birds. But a few years ago, researchers found the well-preserved fossil of Ichthyornis, an ancient toothed bird that lived in the Cretaceous period, in a rock mass 87 to 82 million years ago in Kansas.

This fossil has an almost complete skull, preserving most of the bones that make up the skull.

Torres and colleagues used computerized tomography (CT) to digitally reconstruct the skeleton and brain of Ichthyornis. Morphological analysis shows that ancient birds such as Ichthyornis had "archaic" brains; Its brain resembled the brain of a dinosaur rather than that of modern birds.

Ichthyornis' brain was more like a dinosaur's brain than that of modern birds.

According to Torres, living birds have part of the brain that is much larger than the rest of the brain. The brains of birds today are larger than those of ancient birds and dinosaurs that lived just before the late Cretaceous mass extinction. Since Ichthyornis, a close relative of today's birds, still did not have the large brains of today's birds, scientists deduce that those large brains evolved from ancestors of living birds.

They suggest that the large cerebrum helped the ancestors of today's birds survive the disaster, which helps explain why only some birds survived, but not any other dinosaurs.

•