I had always wondered how the dinosaurs died out. I couldn’t understand how just getting hit by an asteroid, or having volcanoes spew out ash could wipe them all out. Then I heard about some research that pinpoints the moment the asteroid hit. That seemed like a promising place to start my research.

Scientists still debate the specifics of what happened, but it probably went something like this…

Seventy-five percent of all life — plant and animal — died as a result of the impact.
That was the end of the dinosaurs.

Or maybe not.

The burning winds, earthquakes, floods and fires left a few survivors scattered across the globe. But these survivors had to deal with great hardships.

The Earth was a cold, dark, hungry place in the first years following the impact. Without sunshine, plant life, including forests, died. Animals that needed trees for part of their life-cycles died, too.

The fires and darkness left little to eat – rotting trees, fungus, insects, seeds. And of course, survivors had to be able to find the food in the dark. At first, meat-eaters feasted on dead and dying animals. But soon they suffered, too, as their prey died off. Only smaller animals made it through the hungry times of the long cold night.

A decade after the asteroid hit, the skies cleared enough for shade-tolerant ferns to grow again. Eventually other plants and trees sprouted, too. The few animals who made it through the impact and years of starvation and cold finally had something to eat besides fungus, decaying trees and a dwindling number of ten-year-old seeds.

Who survived?

Sea life was impacted least. Creatures who lived deeper in the oceans suffered less than those closer to the surface.

On land, survival was more random. Those who made it through had two common traits — they were small, and they lived on the ground. This included some frogs, turtles, crocodiles, snakes and lizards. These cold-blooded animals probably survived in the tropics. It was warmer there, even in the dark.

Almost as many mammals died in the extinction as dinosaurs. Mammals evolved at the same time as the dinosaurs. But mammals had always been mouse-like creatures. They never grew to the enormous sizes of the dinosaurs.

Their small size meant that mammals required fewer calories. Being small helped them live through the hungry time. And they were used to eating more different foods than most dinosaurs, including seeds, and maybe fungi.

Early mammals lived in many different environments. The mammals that lived in trees died out when the asteroid hit. But a few scurried through the plant litter on the ground, retreating to burrows in times of danger.

As they evolved, many mammals came out in the cool night, when the cold-blooded reptiles slowed. This gave the mammals several adaptations that helped them stay alive when the asteroid hit. They had bigger eyes to see in the dark. Warm blood let them stay active in the cooler hours, and fur insulated their bodies to retain body heat. After the asteroid, their fur also may have protected the mammals from the razor-sharp edges of shattered volcanic glass that littered the ground.

As plant life slowly returned, mammals rebounded quickly. They adapted and filled the empty niches left by the extinction of so many other animals.

Mammals were joined in the empty landscape by a few other creatures. One tiny group of dinosaurs was able to solve the same problems that plagued mammals.
Some of these creatures were ground-dwellers, so they survived the loss of trees. They learned to lay their eggs in protected areas such as rocky ledges or hidden depressions in the soil. They had fingernail-like beaks instead of skin-covered muzzles. The hard beaks may have helped them to find seeds in the razor-sharp layer of ash laid down by the explosion.

In many ways, these animals were like mammals. They were warm-blooded. They became smaller. They made it through the decades long cold spell with a layer of insulation — feathers — that had evolved before the asteroid.

Wait … warm-blooded, beaked, egg-laying, feathered animals … sound like birds.

Yes, birds are dinosaurs, the only group of dinosaurs to survive the asteroid extinction. Dinosaurs didn’t die out, after all.

What we’ve learned from the asteroid extinction is both reassuring and terrifying. Life can survive huge changes that happen in an instant. But there is no way of predicting who will make it through. And the life that survives won’t be the same as it was before.

The asteroid impact was the fifth global extinction the Earth has seen. We are entering the sixth, carbon dioxide global extinction. If we take action now, we can limit the loss of species, and prevent global ecosystem collapse.

But we must take action now. We must do everything we can to limit carbon dioxide production. And it must be all of us, together.

Or we can expect to go the way of the dinosaurs.