When birds evolved from dinosaurs in the Jurassic period (about 150 million years ago), they were tiny creatures like the ones we see on a regular basis. Many of these smaller birds evolved into beautiful parrots, others into waterbirds, and some would become aggressive predators. In every ecosystem there are always apex predators that find a niche at the top of the food chain. Behold Phorusrhacidae, commonly known as the Terror Birds.
These monstrosities were up to 3 meters high and could swallow a dog in a gulp. Their heads were the size of a horses. One of the largest, Phorusrhacidae titanis, was the only one to travel into North America when the bridge between South and North America had formed. This migration and intermixing of species was called the Great American Interchange and P. titanis’ habitat reached form Texas to Florida according to fossil specimens.
Some terror birds, specifically Mesembriornis, could run at over 60 miles per hour, comparable to that of a cheetah. And since they were flightless, their bones were found to be dense enough to be used to shatter the bones of their prey to reach the delicious marrow inside. Yummy!
It fascinates me how dinosaur-like these birds had become. Even though they existed only 2 million years ago, they demonstrate similar characteristics to theropod dinosaurs that went extinct around 65 million years ago. This sort of convergent evolution occurs if animals are put under similar stressors from their environment. In this case, a predatory lifestyle selected characteristics very similar to those of theropod dinosaurs, which held a similar position at the top of the food chain.
Take for example the “ostrich dinosaurs”, Ornithomimosauria. These dinosaurs had similar body shapes and even evolved beaks. Of course, their arms had not passed through an evolutionary flying adaptation, so they were more handy at grasping.
But what the Terror Birds’ upper limbs lacked in weaponry, their beaks made up for. I know myself the strength of a beak. I once owned an African Grey parrot (named Albert) whose beak had evolved to crush nuts. That thing could bite through my finger if it wanted to. Now imagine a bird towering over you whose beak hadn’t evolved to crush nuts, but rather evolved to crush your skull. Researcher working for the Discovery Channel reconstructed the neck muscles and skull of a Terror Bird and found that it was easily capable of driving its beak into a skull like a sledge hammer. Especially while running as fast as a car….
So if you’re ever asked what your favorite bird is, answer whatever you please but remember that there were birds on this planet a hell of a lot cooler than a bald eagle.