Are Dinosaurs Extinct? Modern Birds Connect us to Our Ancient Past

Despite growing up in rural Illinois, I didn’t pay that much attention to the biological world around me as a kid. I spent far more time thinking about sports and superheroes than anything in nature. Even the mysterious creatures of past eons didn’t grab my attention. (I’m one of the rare paleontologists who wasn’t obsessed with dinosaurs as a youngster!) But as a college student, I finally started paying attention.

In my different biology courses, I engaged with the living world in a host of ways. I used a microscope to study single-celled organisms in pond water. I learned to identify various species of plants in the field. I explored the anatomies of different animals at a high level of detail. I crossed varieties of fruit flies to understand the genetics of different mutations. Each of these experiences nurtured my growing fascination with living things and the unique ways that they have adapted to thrive on this planet.

It was in my vertebrate biology class that I looked at a bird through binoculars for the first time. Ever since then, I’ve appreciated the incredible diversity of birds, but in a fairly casual way. My wife Melissa and I have always paid attention to local species when on walks with our dog. We’ve also long had a bird feeder with generic birdseed hung up outside our house in west Michigan. I’ve even had the privilege to see some rare and exotic species when teaching in Ecuador, the Galápagos Islands, and New Zealand. But the COVID pandemic changed me in a pretty fundamental way: it turned me into a bird nerd.

During the spring of 2020, we invested in some new bird feeders and picked up a few different varieties of birdseed to give us some new forms of in-home entertainment. Pretty quickly, my family and I were hooked. We knew many of the most common species already, but we started to see birds we didn’t recognize. We used field guides and apps like Merlin to help us figure out what we were seeing. We even started to compile lists of exactly which species were visiting our yard using an app called eBird.

It didn’t take long for us to venture a bit farther afield, surveying area parks to add new species to our lists. Sometimes we even went out hoping to see a particular species. For my oldest son Kyler, a scarlet tanager was his holy grail—probably because it graced the cover of the field guide we had gotten him. The look of excitement on his face when we spotted one together for the first time is something I will remember forever.

Certainly, a statement like this can’t be said without generating at least some debate. But since at least the 1860s, some have proposed a link between dinosaurs and birds, especially after the discovery of Archaeopteryx from a limestone quarry in Germany. Initially, this species was known simply from an isolated feather impression in rock. But in the years that followed, several body fossils of this species were discovered as well. I was fortunate to see the Berlin specimen on display during a visit I made to the Museum für Naturkunde in Berlin in 2014. But long before then, I had the chance to study a cast of this specimen in my undergraduate paleontology course at Calvin College.

I remember compiling a list of features that suggested Archaeopteryx was a bird. It had clear feather impressions in the limestone surrounding its body and long, wing-shaped arms. It even had a wishbone (what anatomists call a furcula). But at the same time, it had many features that seemed distinctly reptilian in nature. It had claws at the ends of its fingers, which didn’t fuse together as they often do in birds. It had a long bony tail, sacrum, and pelvis that lacked the elaborate fusion evident in the synsacrum of birds. Its upper and lower jaws were full of teeth.

If pressed to define whether Archaeopteryx were a bird, I probably would have said yes. But I also would have pointed out that things were a bit fuzzy given the strange mixture of traits it had. Were it not for the feathers, I probably would have identified it as a dinosaur. In fact, one specimen of Archaeopteryx was actually misidentified as a small dinosaur for a couple of decades due to the lack of clear feather impressions surrounding the bones!

Certainly, there are still many open questions here. How exactly are all these different groups of ancient species related, and which are the most closely related to modern birds? Why and how did avian flight come about? Why and how did feathers develop—did it have anything to do with ancient dinosaurs and their kin being warm-blooded? Future discoveries will undoubtedly help to answer some of these questions, while at the same time throwing some of our currently favored hypotheses into disarray. But given what we do know, it seems pretty reasonable to say that dinosaurs did not go extinct 66 million years ago after an extraterrestrial rock collided with our planet. Some of them managed to survive and diversify into one of the most speciose groups of vertebrates on Earth today.