Tech

These images show dinosaurs aren't really 'extinct' after all

Sean Kane and Lauren F Friedman

2016-03-15T20:14:40Z

The dinosaurs never really went extinct — at least not in the way you might imagine. Instead, many of them evolved into a class of animals that's still very present on our planet: birds.

A new exhibit at the American Museum of Natural History, "Dinosaurs Among Us," shows how enormous, fearsome beasts like the Tyrannosaurs Rex became parrots and chickadees. This transition wasn't quick, and many of the famous dinosaurs we know today, like the T. Rex, sported feathers long before they resembled anything close to modern birds.

Check out these weird transitional forms that have changed much of what we thought we knew about the dinosaurs that ruled the Earth hundreds of millions of years ago.

Dinosaurs like the Yutyrannus huali, a 1.5 ton relative of T. rex that lived 125 million years ago, were covered in feathery fuzz. When scientists discovered this beast in 2012, it was some of the first concrete evidence that <a href="http://www.smithsonianmag.com/science-nature/scientists-discover-a-gigantic-feathered-tyrannosaur-172633563/?no-ist">even the mighty T. rex might have been sort of fluffy</a>. The name means "beautiful feathered tyrant."

3b."Yutyrannus huali" “ beautiful feathered tyrant,” 1.5 tons related to T.Rex northeast china 2012

While <a href="https://www.theguardian.com/science/lost-worlds/2012/oct/17/dinosaurs-fossils">the jury is still out on whether the T. rex itself had feathers</a>, many scientists <a href="http://www.nature.com/news/palaeontology-the-truth-about-t-rex-1.13988>">now think</a> they might have had some kind of proto-feathers — Jurassic Park be damned.

The T. rex even had a wishbone. Scientists once believe these bones (technically called furculae) helped strengthen bodies for flight. But this wishbone from the giant, earthbound T. Rex showed that its purpose was not just for flying.

So if feathers weren't for flight, what use were they? There are few theories. One clue came from X-ray studies, where scientists noticed that modern baby birds flapped their wings to aid them in climbing steep slopes. Paleontologists believe that dinosaurs may have used their rudimentary wings for this purpose, long before they could fly.

The Citipati osmolskae — another flightless, feathered dino — looked nothing like a T. rex, but both were therapods: carnivorous dinosaurs that walked on two feet — and eventually <a href="http://www.ucmp.berkeley.edu/diapsids/saurischia/theropoda.html">evolved into modern birds</a>.

5a. Citipati osmolskae (citipati are dancing skeletons that protect funeral pyres, osmolskae was a polish paleontologist known for Gobi desert exploration)

This fossil of Citipati osmolskae was an important find: It provided <a href="http://naturalhistory.si.edu/exhibits/backyard-dinosaurs/how-did-dinosaurs-behave.cfm">evidence that dinosaurs cared for their young</a>. It seemed to be protecting its eggs with its forearms, a position modern birds use when brooding (also known as sitting on their eggs).

4. Citipati osmolskae protecting eggs (many birds use this position when brooding)

This Khaan mckennai was an oviraptorid, a small, birdlike dinosaur that — scientists believe — also sat on its eggs.

The velociraptor is a good illustration of the dinosaur-bird transition. It had birdlike feet with three front-facing toes, hinged ankles, and feathers on its forearms and tail that <a href="http://animals.nationalgeographic.com/animals/prehistoric/velociraptor-mongoliensis/">may have been used as a mating display</a>.

But not all feathered dinosaurs were famous, fearsome theropods like T. rexes and raptors. Sinornithosaurus had limbs that were covered in feathers (similar to modern birds), but it was not capable of flight. <a href="http://www.theguardian.com/theguardian/2000/feb/07/features11.g22">Its discovery in 1996</a> was an early suggestion that birds and dinosaurs might be directly linked.

While many dinosaurs are now depicted with feathers, we can't know exactly what they looked like — or what color their feathers were. The Byronosaurus, shown here, was a large brained dinosaur who lived in the Late Cretaceous period, about 80 million years ago.

This Byronosaurus died while it was in the middle of hatching, surrounded by non-hatched eggs.

This dinosaur, a microraptor, is one of the smallest known dinosaurs — and among the most birdlike. It had feathers on both its front and hind legs. In 2008, when NOVA interviewed Yale paleontologist Jacques Gauthier about the puzzling discovery of the microraptor, he <a href="http://www.pbs.org/wgbh/nova/evolution/four-winged-dinosaur.html">put it plainly</a>: "Birds are dinosaurs. That's why they look like dinosaurs."

Even with feathers, though, most dinosaurs looked very little like the birds we know today. Anchiornis huxleyi, which lived in what is now China 161 million years ago, wasn't even capable of powered flight. But its wings provided enough lift to jump to advantageous perches and glide.

The Confuciusornis sanctus, however, is considered a bird — not just a bird-like dinosaur. It already had many features of modern birds, like a beak and a feathered tail, though it probably couldn't fly well. It didn't have the strong breastbone needed to support powerful wing muscles.

Archaeopteryx was considered the first true bird when scientists discovered it in 1861. Found shortly after Charles Darwin proposed his theory of evolution, it's an excellent transitional example of evolution at work. With teeth and claws but also feathers and wings, it's seen as <a href="http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html">a key link between birds and reptiles</a>.