Isn't the world full of interesting creatures? We enjoy spending time with cats and dogs as constant companions at home. When we venture into the wild, we might see deer, foxes, and rabbits. A trip to the zoo reveals a whole new world of exotic creatures, from whales and snakes to orangutans and giraffes.
But what if we took a journey back in time? Can you imagine what it would've been like to live during the time of the dinosaurs? Foraging for nuts and berries would've been much more interesting if a sighting of a Stegosaurus or a Tyrannosaurus Rex was possible.
Alas, a cataclysmic disaster wiped out all the dinosaurs…or did it? Could there be dinosaurs still living with us here on Earth? Scientists would argue that, in a sense, dinosaurs are still alive in the form of the animals that evolved from them.
What animals evolved from dinosaurs? We certainly don't see anything like a Tyrannosaurus Rex roaming Earth these days. Perhaps we're focusing our eyes in the wrong direction, though. To find the descendants of the dinosaurs, scientists would tell us to look up to the skies.
That's right! Modern scientists believe the birds that fill the skies of the world are the living descendants of the dinosaurs. This isn't an entirely new idea, though. Ever since the 19th century when scientists discovered the fossilized remains of Archaeopteryx, a bird-like dinosaur, researchers have worked to bridge the gap between ancient reptiles and modern birds.
Archaeopteryx is very significant to the scientific community because it had features characteristic of both dinosaurs and birds. Unlike birds, it had a full set of teeth, a long tail, grasping claws at the end of its wings, and other anatomical features typical of dinosaurs. But unlike dinosaurs, it had feathers, wings, reduced fingers, and some other anatomical features modern birds possess. Archaeopteryx is considered by many to be the first bird on Earth and it lived 150 million years ago.
Over the last several decades, scientists have discovered fossils from a wide variety of other types of bird-like dinosaurs. Based upon these findings, scientists now firmly believe that modern birds evolved from a group of dinosaurs called maniraptoran theropods.
This group of dinosaurs included usually small, meat-eating dinosaurs. One example is Velociraptor, whose name you may recognize if you're familiar with the movies Jurassic Park or Jurassic World. The movie version of Velociraptor was quite a bit different from the real creature, however. Unlike the creature in the movies, the real Velociraptor was likely much smaller and not nearly as fierce.
How can scientists know that modern birds evolved from these bird-like dinosaurs that lived 100 million or more years ago? Scientists rely on several different types of evidence to support their views.
For example, scientists first noticed striking similarities in bone shape between modern birds and their ancient predecessors. Adding to this powerful evidence, scientists have also learned that maniraptoran theropods laid eggs in a way similar to modern birds — and the eggs themselves resembled the eggs of modern birds.
Some of the most compelling evidence, though, has come from recent discoveries that many of the maniraptoran theropods had feathers. For many years, birds were thought to be unique in that they had feathers. Scientists now know that their dinosaur predecessors had them, too, and may have also flown!