When the big asteroid hit Mexico 66 million years ago, it set off wildfires, tsunamis and massive clouds of dust that darkened the skies, killed much of Earth’s plant life and triggered a chain of ecological catastrophes that led to the rapid extinction of most of the dinosaurs.
But some life survived, including mammals that may have taken refuge in burrows and scavenged. There were also many small, feathered, hollow-boned dinosaur species that somehow survived. Their descendants are still with us today — around 10,000 species of small, feathered, hollow-boned animals that we call birds.
The category of “reptiles” contains birds. Lizards, snakes, crocodiles and turtles are commonly classified as reptiles because they all share a common ancestor, some scaly, cold-blooded creature that evolved almost 300 million years ago. From that ancestor, the turtles split off very early, soon after the mammals. Mammals evolved from an early reptile long before there were dinosaurs. If turtles and dinosaurs are reptiles, then birds must be also because they have the same reptile ancestor in common.
Eventually dinosaurs evolved and dominated Earth for almost 200 million years. Some dinosaurs in the group called theropods, which contained the fearsome Tyrannosaurus rex, had fuzzy little feathers. Therapods included small, flighted, bird-like dinosaurs with proper feathers, and they survived the Crash of 66 — the Cretaceous-Paleogene extinction event that occurred 66 million years ago.
We know this all from fossil evidence. First, there was the discovery of archaeopteryx, which is a pigeon-sized dinosaur with many bird-like characteristics, including very modern-looking wing feathers and a wishbone, but also a long, heavy tailbone, a mouthful of teeth, and clawed hands like a dinosaur. Archaeopteryx lived about 150 million years ago, but there were other birdlike dinosaurs even before that. The discovery of archaeopteryx in 1860 was a sensation, coming as it did just a year after the publication of Darwin’s incredibly controversial book “On the Origin of the Species by Means of Natural Selection.”
Darwin laid out with painstaking detail what is still our modern understanding of evolution by gradual change of one species to another. He challenged the common understanding that God had made all creatures and suggested that, instead, each form of life had evolved from something older, through gradual changes that helped it survive better in a changing environment. As if made to order, a fossilized archaeopteryx feather appeared the next year on a slab of quarried limestone, and then a whole skeleton of something that looked exactly like a dinosaur evolving into a bird.
But archaeopteryx went extinct and is not the ancestor of modern birds, just one of many feathered dinosaurs that resembled birds. Science’s obsession with archaeopteryx was a bit of a diversion and may be the reason that our current understanding of birds as dinosaurs required another century to become accepted as fact.
Other bird-like dinosaurs survived and are still with us today, entertaining at our bird feeders, providing a meal at Thanksgiving, migrating to the tropics at night over our illuminated cities, serving as fierce national icons or the symbol of peace, inspiring artists. Semantics aside, these are dinosaurs.
Dan Cristol teaches in the biology department at William & Mary and can be contacted at dacris@wm.edu. To discover local birding opportunities visit williamsburgbirdclub.org.
https://www.dailypress.com/2025/08/28/birding-dinosaurs-are-not-extinct/
