Is there a dinosaur in your back yard?

Whether in your back yard or on the golf course, you do not want to run into a Tyrannosaurus rex. Don't miss the fun facts about T. rex at the bottom of this page. (By the way, my friends Carol and Martha were not harmed in making this photo.)

Whether in your back yard or on the golf course, you do not want to run into a Tyrannosaurus rex. Don't miss the fun facts about T. rex at the bottom of this page. (By the way, my friends Carol and Martha were not harmed in making this photo.)

You may have learned in school that all dinosaurs are extinct. However, thanks to new fossil finds, advancing technology and some pretty smart research, scientists now know that while most of the dinosaurs bit the dust 66 million years ago, there's one branch of the dinosaur family tree that survived. Depending on where you live, you might have a dinosaur in your back yard!

QUIZ!

Do you know which of these is a living dinosaur?

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Alligators, armadillos, birds and turtles have all been known to show up in my back yard from time to time. However, only one is a living dinosaur. Were you able to guess which one? Let's look at them one at a time.

Armadillos

Nope. Armadillos do have a strange, prehistoric look, but they aren't dinosaurs. Armadillos are mammals; dinosaurs were reptiles. Some mammals were around during the age of the dinosaurs, but they were mostly small, rat-like creatures that just scurried around trying not to become a dinosaur's breakfast. It was only when most of the dinosaurs went extinct 66 million years ago that mammals came to rule the planet. As for armadillos, they evolved in South America over a million years ago.

The glyptodont - an extinct relative of living armadillos - was about 9 feet long and very heavily armored, including a spiked knob at the end of its tail for thwacking its predators. I would not want to see that in my back yard! (Drawing © N. Tamura, placed in Wikimedia.)

The glyptodont - an extinct relative of living armadillos - was about 9 feet long and very heavily armored, including a spiked knob at the end of its tail for thwacking its predators. I would not want to see that in my back yard! (Drawing © N. Tamura, placed in Wikimedia.)

Turtles

Negative. Turtles aren't dinosaurs, either. They've been around just as long, though, appearing during the Triassic period more than 200 million years ago. The earliest ones had bony plates for protection, but hadn't yet figured out how to pull their heads inside their shell.

There were lots of turtles around during the days of the dinosaurs. The biggest one - the Archelon - was 10 feet long and had a 13 foot flipper span. It had a bony framework for protection instead of a solid shell. Otherwise, it would have been so heavy it would have sunk like a rock. (Photo by Frederic A. Lucas, placed in Wikimedia.)

There were lots of turtles around during the days of the dinosaurs. The biggest one - the Archelon - was 10 feet long and had a 13 foot flipper span. It had a bony framework for protection instead of a solid shell. Otherwise, it would have been so heavy it would have sunk like a rock. (Photo by Frederic A. Lucas, placed in Wikimedia.)

Alligators

Nuh-uh. Close, but not dinosaurs. Alligators and other crocodilians have a common ancestor with dinosaurs - the archosaurs. That makes alligators and dinosaurs sort of like cousins. You might be interested to know that during the Triassic period (250 - 200 million years ago), crocodilians were large and in charge. Some were over 25 feet long, and they were quite ferocious. They lived on land, and didn't necessarily look a lot like modern crocodiles and alligators. Some even walked around on two legs. How would you like to see that in your back yard? During this time, dinosaurs were mostly very small, and went out of their way to avoid the scary, scary crocodilians.

Then, around 200 million years ago, there was a mass extinction event that wiped out many species on the planet. The cause of this event is still debated, though climate change as a result of unbelievably massive volcanic eruptions frequently falls under suspicion. The larger crocodilians went extinct, which enabled dinosaurs to take over their role as the biggest baddies on the planet. Some smaller crocodilians survived and started living in the water to avoid the big dinosaurs, eventually evolving into alligators. By the time most of the dinosaurs went extinct 66 million years ago, alligators were already pretty similar to what we see around today, indicating they are incredibly well adapted to their environment.

While most of the crodocilians that survived the mass extinction 200 million years ago stayed small, a few evolved into huge monsters. Deinosuchus is a good example. It was a force to be reckoned with 80-73 million years ago in the area that is now the southeastern United States. It basically looked like today's alligators - but much, much bigger. It was up to 35 feet long, weighed up to 6,000 pounds, and had a bite force greater than a T. rex. It hunted in the water where the big dinosaurs couldn't go, eating lots of turtles and fish. It also nabbed the occasional dinosaur that chose the wrong spot to get a drink of water. (Drawing by Andrey Atuchin, placed in Wikimedia.)

While most of the crodocilians that survived the mass extinction 200 million years ago stayed small, a few evolved into huge monsters. Deinosuchus is a good example. It was a force to be reckoned with 80-73 million years ago in the area that is now the southeastern United States. It basically looked like today's alligators - but much, much bigger. It was up to 35 feet long, weighed up to 6,000 pounds, and had a bite force greater than a T. rex. It hunted in the water where the big dinosaurs couldn't go, eating lots of turtles and fish. It also nabbed the occasional dinosaur that chose the wrong spot to get a drink of water. (Drawing by Andrey Atuchin, placed in Wikimedia.)

Birds

Yes! Birds are dinosaurs!

It seems like an awfully big leap from T. rex to birds. How did scientists figure out that birds are dinosaurs? It took a while. Let's start with my favorite scientist of all time, Charles Darwin. In 1859, Darwin published On the Origin of Species, in which he proposed his theory of evolution through natural selection. This got people thinking (and arguing) about the possibility that a species could gradually change enough over a long period of time to become a new species. Then, just two years later, in 1861, an interesting fossil was discovered in a limestone quarry in Bavaria. Archaeopteryx had sharp claws and a long tail like a reptile, and feathers and wings like a bird. This "missing link" fossil was held up as hard evidence of Darwin's theory of evolution. One of Darwin's biggest supporters, a British biologist named Thomas Henry Huxley, carefully studied Archaeopteryx, other dinosaur fossils and modern birds, and found so many similarities between them that he ultimately concluded there was an evolutionary link between birds and dinosaurs. That idea got a lot of eye-rolling, but it didn't get universal support. There wasn't enough proof.

Archaeopteryx lithographica is considered the oldest bird in the dinosaur fossil record, going back 150 million years. You can barely make out the feather impressions in this fossil. (Photo by H. Raab, placed in Wikimedia.)

Archaeopteryx lithographica is considered the oldest bird in the dinosaur fossil record, going back 150 million years. You can barely make out the feather impressions in this fossil. (Photo by H. Raab, placed in Wikimedia.)

Based on fossils, scientists are able to determine what archaeopteryx would have looked like. They were about the size of a crow and probably were mostly black. Scientists have not been able to determine if they were capable of flapping flight, or whether they were just gliders. (Drawing by Durbed, placed in Wikimedia.)

Based on fossils, scientists are able to determine what archaeopteryx would have looked like. They were about the size of a crow and probably were mostly black. Scientists have not been able to determine if they were capable of flapping flight, or whether they were just gliders. (Drawing by Durbed, placed in Wikimedia.)

Now let's fast-forward over 100 years to the 1970s, when there was what paleontologists refer to as a Dinosaur Renaissance - a renewed enthusiasm for the study of dinosaurs. Thanks to new fossil finds - and new technologies with which to study them - scientists were beginning to understand that dinosaurs weren't just big, dumb, lumbering creatures destined for extinction. On the contrary, dinosaurs were actually smart, highly active, evolutionary marvels. They had a lot of things in common with animals living today - especially birds.

Eventually, in the 1990s, even more fossil finds helped provide the final proof that birds are dinosaurs. Huxley turned out to be right after all! First, the new fossils showed that dinosaurs evolved feathers even before birds evolved into existence. Birds didn't invent feathers; dinosaurs did. And, the fossils showed us exactly where birds roost on the dinosaur family tree. There are three main groups of dinosaurs, each of which has many sub-groups. Ornithischians include the armored dinosaurs such as Ankylosaurus and Stegosaurus. Sauropods include the gigantic long-necked herbivores such as Apatosaurus and Diplodocus. Theropods include the super scary meat-eaters like Tyrannosaurus rex and Velociraptor.

Guess where birds fit in? They're theropods! Specifically, birds are in a sub-group of theropods called paravians. This group of dinosaurs was smaller, nimbler and even smarter than the biggest theropods like T. rex. Once flight evolved, evolution really took off. Over millions of years, birds changed quite a bit to take advantage of this huge innovation. They got smaller and lighter, developed longer arms and bigger chest muscles to power flight, lost their tails and teeth, and developed more efficient breathing. As they became better flyers, birds were able to move into more habitats and diversify into many species. They lived in trees, on the ground, or on the water like ducks. Birds that looked a lot like the birds we know today were living alongside tyrannosaurs and velociraptors.

I know it seems crazy to think of birds as being in a family of ferocious meat-eaters, but modern raptors such as hawks, eagles and ospreys must look as ferocious as a T. rex to their prey.

I know it seems crazy to think of birds as being in a family of ferocious meat-eaters, but modern raptors such as hawks, eagles and ospreys must look as ferocious as a T. rex to their prey.

Extinction of the non-bird dinosaurs

So what happened? How did the world transform from one dominated by big, scary dinosaurs to one where only the birds remain? It all started with an asteroid impact. 66 million years ago, on April 1, an asteroid six miles wide slammed into the Earth off the coast of what is now known as the Yucatan Peninsula, leaving behind a crater that's about 100 miles wide and 12 miles deep. Ouch. I'm kidding about the April 1 part, but the bit about the asteroid is well-accepted science.

The asteroid impact resulted in a super horrific day for planet Earth. There are some pretty graphic descriptions out there of the havoc wreaked by the asteroid. Suffice it to say, it involved terrible earthquakes, tidal waves 1,000 feet high, shock waves hot enough to start raging forest fires, and showers of scalding hot debris. Many of the dinosaurs were killed instantly - even if they were 2,000 miles away in Montana. Then, over the next couple of years, all of the dust and debris in the air caused the Earth to turn cold and dark. Without sunlight, many plants died, food chains were broken and entire ecosystems collapsed. That finished off many of the animal species that were hanging on for dear life. By the time all was said and done, the planet had seen a mass extinction event that killed an estimated 70% of all animal and plant species. This is referred to as the K-Pg extinction because it marks the boundary between the Cretaceous period (designated by K because C was already used for the Carboniferous period) and the Paleogene period.

How did the birds survive?

Did birds just get lucky? Maybe a little bit. A lot of birds perished in the K-Pg extinction, too, but many were well suited to weather the storm. In the face of the asteroid impact's immediate and more lasting effects, it helped to be small and nimble, and to have fur or feathers for insulation from the cold. It also helped if you could fly, burrow or swim. Right after the impact, smaller birds and mammals that were able to fly or scamper away to a safe place were the ones that survived. After cowering in the shadow of the big meat-eating dinosaurs for 100 million years, it looks like they got the last laugh. Turtles and alligators were able to hide out underwater. It was also helpful to have a flexible diet - especially one that included seeds (which can survive harsh conditions for many years) or detritus (which there was gobs of after the impact). Fortunately, some birds had already evolved to have seed-based diets before that fateful day.

While the K-Pg extinction was quite dramatic and sad in many ways, extinction of the non-bird dinosaurs ultimately enabled birds and mammals to flourish, eventually evolving into the creatures we know and love today. While I find dinosaurs to be very interesting, I'm quite happy I'll never see a tyrannosaur in my back yard. In fact, I'm pretty sure humans never would have evolved into existence at all in a world ruled by dinosaurs.

Transition to modern birds

Once the dust settled - both literally and figuratively - new ecosystems formed and life continued to evolve to suit those new homes. Now that the huge meat eaters were gone, the survivors started to evolve into larger animals. By 55 million years ago, some birds were huge, flightless creatures weighing over 600 pounds, but most birds were smaller so they could capitalize on the advantages of flight. The ability to fly enabled birds to easily move into new environments and to capture many different types of prey. Over millions of years, birds evolved and diversified into the wide range of birds that grace our planet today.

Gastornis was a huge, flightless bird that lived 55-45 million years ago. Note how it related in size to humans (but of course there were no actual humans way back then). Gastornis is related to the waterfowl we see today. (Drawing by Tim Bertelink, placed in Wikimedia.)

Gastornis was a huge, flightless bird that lived 55-45 million years ago. Note how it related in size to humans (but of course there were no actual humans way back then). Gastornis is related to the waterfowl we see today. (Drawing by Tim Bertelink, placed in Wikimedia.)

Dinosaurs are arguably the most successful animals in the history of planet Earth. They've been around now for 230 million years, having ruled the planet for 150 million of those years. Dinosaurs witnessed the break-up of supercontinent Pangaea into Earth's current arrangement of seven continents, survived the K-Pg extinction, and saw ice ages come and go. Dinosaurs are still with us today as modern birds, but the new rulers of the planet - humans - aren't making it easy for them. Habitat loss and climate change are happening too fast for some birds to adapt. As a result, one in eight bird species is threatened with extinction globally. Right here in Florida, 31 bird species are on the threatened or endangered list. We can all show dinosaurs some love by protecting our planet. We always want to find dinosaurs in our back yards!


Fun Facts about T. rex

Tyrannosaurus rex has a reputation as the scariest dinosaur of all time - and for good reason. It grew to 42 feet long, weighed seven to eight tons, and had a mouth full of razor sharp teeth. It was a serious meat-eater feared by all other dinosaurs. Its powerful jaws were capable of easily crushing bones, and were probably strong enough to bite right through a car.

T. rex probably ambushed its prey. It could run at 10-25 miles/hour, which is pretty speedy, but not fast enough to chase down a lot of its favorite meals. Plus, it was too big for any zigging and zagging. (It would have been able to outrun a human though!) Even scarier, T. rex traveled and hunted in packs!

T. rex had a big brain, so paleontologists believe it was quite intelligent - probably as smart as a chimpanzee, and definitely smarter than cats and dogs. (Those of us who believe our pets are brilliant are horrified by that.) T. rex also had very good senses of hearing, smell and sight.

T. rex had a lot in common with birds, which is not surprising since they were on the same branch of the dinosaur family tree. They hatched from eggs and grew very quickly. They had air sacs in their bones (pneumatic bones) to help keep their weight down. They also had wishbones - just like your Thanksgiving turkey, but a lot bigger. Like today's birds, T. rex had lungs that could pull oxygen out of the air when breathing both in and out. This gave them a lot of stamina for their active lifestyle. Last but not least, T. rex had another very interesting thing in common with birds: feathers! While it had thick, scaly skin like a reptile, there were feathers sticking out from between the scales. Their feathers would have been more primitive and hair-like than the feathers birds sport today, but I still think it's pretty cool that T. rex had feathers.

T. rex was a late-comer on the dinosaur scene, living in what is now North America from 68-66 million years ago. (FYI, for you fans of Jurassic Park, that's well after the Jurassic period ended 145 million years ago.) So T. rex had only been around for two million years when it and the other non-bird dinosaurs went extinct. Two million years sounds like a lot, but that's not really all that long given that dinosaurs ruled the planet for 150 million years. Tyrannosaurus rex no longer roams our planet, but it is certainly still the king among dinosaurs!


Tyrannosaurus rex, the "tyrant lizard king." (Drawing by Durbed, placed in Wikimedia.)

Tyrannosaurus rex, the "tyrant lizard king." (Drawing by Durbed, placed in Wikimedia.)


Pterosaurs were not dinosaurs

We've all seen pictures of pterosaurs flying around, and they sure look like dinosaurs, but they aren't. Like crocodilians, pterosaurs are close cousins of dinosaurs, descending from a common ancestor: the archosaurs. Pteroaurs (sometimes called pterodactyls) were the first vertebrates to evolve wings and fly. Their wings were actually flaps of skin attached to one of their fingers. Pterosaurs typically flew around over water and caught fish. Mostly, they were the size of today's birds, but some of them got really big (and terrifying). To help keep their weight down for flight, pterosaurs had air sacs inside their bones - something they had in common with birds and other theropod dinosaurs. To help them regulate their body temperature, they had hair-like filamants called pycnofibers. Pterosaurs all died out during the K-Pg extinction.

***

Why can't you hear a pterosaur go to the bathroom?

Because the "p" is silent!

With a 39-foot wingspan, Quetzalcoatlus was the largest pterosaur - and the largest flying animal in the entire history of the planet. It flew over land and ate dinosaurs! (Model created by René Kastner, Staatliches Museum für Naturkunde Karlsruhe, Germany; photo by H. Zell, placed in Wikimedia.)

With a 39-foot wingspan, Quetzalcoatlus was the largest pterosaur - and the largest flying animal in the entire history of the planet. It flew over land and ate dinosaurs! (Model created by René Kastner, Staatliches Museum für Naturkunde Karlsruhe, Germany; photo by H. Zell, placed in Wikimedia.)


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