Archeologists and anthropologists are scientists who study the past. They hunt for signs of old civilizations. But fossils and what remains of ancient cities are buried under thousands and millions of years of sand and dirt and decomposed matter. So how do they find traces of the past? Archeologists have an idea of where to look, and they ask for help. Here’s a story from National Geographic which shows how sometimes you need to have a little knowledge, a lot of luck and work with what you have to make an awesome find.
In South Africa, near Johannesburg, archeologists and anthropologists have found important fossils. Lee Berger, an anthropologist and professor from the University of Witwatersrand, in Johannesburg, had a feeling there were more fossils in the area. He put the word out not just to scientists, but to cavers too.
Steven Tucker and Rick Hunter, were having fun spelunking—caving—in the Rising Star cave in Johannesburg. While Hunter focused his camera to take a picture of a cave, Tucker stepped back to get out of the way. What happened then was the first step to a huge archeological find. The step was into a chute—a channel that dropped down. In some places, it was only eight inches wide. Tucker didn’t fall, but he and Hunter both followed the chute, down, forty feet, into another cave. And that’s where they found the surprise of their lives. The cave was full of bones. The bones looked human. They remembered Berger, the anthropologist.
Although Tucker and Hunter found the bones, it takes scientists to be able to identify the bones, tools and artifacts in an ancient site. But, of course, there was a problem. A scientist would have to be very small to be able to get back into the site Hunter and Tucker found. It would also help—a lot—if that scientist had caving experience. Professor Berger took charge of the operation, but he needed small scientists with caving experience—scientists who could get through two very, very skinny channels to get to the bones. What to do? Facebook! He found six small scientists with caving experience—all six young women. They were all either anthropologists or archeologists. Most of them were still studying their field. They knew how to handle specimens, preserve them and catalogue them. In three weeks, they took out 1200 well preserved bones. The bones were from an ancient species—not quite apes and not quite humans. This new species is now named Homo Nadeli. The bones have not been dated yet. That will come. I’ll let you know about it. But what interests me in this story is that sometimes science takes unexpected twists. Sometimes luck plays a part in mayor discoveries. And if you’re a scientist, you have to be really creative to get results.
Everybody Wants to Live!
In my newest book, Sounds of the Savanna, a lioness captures a gazelle. The last page of the book, shows her cubs—happy with full tummies. AWWWWW! I hate it when any animals get killed. I love the illustrations of the sweet little cubs. But they ate a gazelle. Probably some mother gazelle’s little baby.
I hate it, I hate it, I hate it.
But when I think about it, lions are carnivores. They don’t have a choice—they have to eat meat. Their bodies are not made to eat grass. The lioness, and other lionesses in her pride, provide food for the lion, themselves and the cubs. Lionesses have to hunt so they can keep hunting, so they can feed their cubs, so their cubs can grow up to have babies of their own, and their babies can have babies and the species will continue to exist. Lionesses need to hunt so there will always be lions on the savanna and other parts of Africa.
Lionesses hunt because they want to live. Other predators hunt because they want to live. Prey animals in the savanna like wildebeests and zebras and gazelles and monkeys have developed behaviors and adaptations so that maybe the lionesses and other predators won’t be so successful. Prey want to live as well. Everybody wants to live!
Even though I’m not crazy about lions killing cute little gazelles, I can understand why they have to. And when I studied them when I was writing Sounds of the Savanna, I found lots of cool facts about lions. About how they live. About how they hunt.
In a pride, (that’s what we call a group of lions), there is one adult lion, several lionesses which are related and their cubs. Young lions leave the pride when they’re mature. The lionesses do most of the hunting. When they bring back a kill, the lion eats first, then the lionesses, then the cubs. Can you figure out why that is? The lions protect the pride from predators or other lions which may want to hurt the cubs. Definitely, protection is most important. The lionesses eat next. i bet you can figure they eat next because they are the ones who bring dinner home. If the lioness dies, the cubs don’t eat. No more cubs, no more lions. It makes sense the cubs eat last. And of course, they don’t need as much meat.
Lions take the protection thing very seriously. When the lion of the pride begins to get old and is unable to protect the pride, a younger lion fights him for the pride. If the lion wins, he stays, but if he looses, he’s out. The younger lion becomes the “king” of the pride. One bad thing that this new lion will do, though, is to kill all the babies in the pride.
Lionesses often hunt in groups. They each have a job. Some may distract the prey while others attack. When lionesses cooperate, they can bring down bigger prey. When a lioness hunts alone, and also when those lone lions hunt, they go for smaller prey like gazelles.
When babies are born, there is a sort of nursery in the pride where all the babies hang out. Lionesses will nurse other lionesses babies. They teach their babies to hunt. After two years, the cubs are able to hunt for themselves.
Lions and lionesses are lazy. They rest about 16 hours every day. But the best thing that I like about lions is that only kill one out of every five times they hunt. Gazelles have a pretty good chance against them.
You’re taking your sandwich out of your lunch bag when the kid sitting next to you yells, “Look, an eagle!” Of course there’s no eagle, and when you get back to your sandwich, it’s gone. Bummer. Double bummer. What a nasty kid! Would it help if you knew that you’re not alone? Scientists Aaron Corcoran found that some Mexican free-tailed bats can be like the cafeteria bully.
All bats hunt for food by broadcasting very, very high pitched sounds. These ultra sonic sounds are so high pitched, humans and most animals can’t hear them. The bats listen for the sounds to strike something—maybe a juicy moth, or a crunchy beetle—and bounce back to them. This is called echo-location. Dolphins use it too. Navy ships use it too—they call it sonar. They send out high frequency pulses, and listen to the bounce, the echo. Doing this, the bats, the dolphins and the captains of ships can “see” in the dark through the sound waves that bounce back to them. Have you seen a sonogram of a baby inside the mom’s tummy? Yep. Same thing.
Bats and dolphins use echolocation to zero-in on food. When a bat is closing in on the kill, they send out more and more signals, one right after the other. Scientists call this a “feeding buzz.” Aaron found out that when a Mexican free-tailed bat zeroes in and starts buzzing, a bully bat, sends signals at the first bat, as if they were echoes. The new signals jam and confuse the first bat, and then the bully sneaks through to get it’s dinner. But it’s not so easy as it would seem for the bully bat. Often the first bat sends its own jamming signals and they’re off in a high frequency duel to see who gets the food.
How did Aaron figure this out? He was listening to Mexican free-tailed bats in Arizona using ultra frequency microphones. He heard something different. He and another scientist, William Conner, set up an experiment. They tied live moths to fishing line, and let them fly in the bat colony. When a bat started the feeding buzz, played the new call they had recorded. When they did this, the bats had a much harder time spotting the moth than when they didn’t play the recording. Normally, bats catch a prey two out of three times they hunt. With the recording, they only caught prey one out of every five times. These bats jam the communications of other bats just like in war soldiers try to jam each others’ communications.
Mexican free-tailed bats aren’t the only ones that communicate about food. In an article in Smithsonian Magazine, Michelle Nijhuis talks about the big brown bat, a North American bat, which chirps to tell other bats they’ve got the rights to a bug. A European bat has sounds that warn other bats away from their area. These bats use their vocalizations to warn others away from their food, but they’re not bullies!
I learned the information to write this article from National Geographic Magazine and from an article written by Michelle Nijhuis for Smithsonian Magazine.
First you hear them. Their cackling and purring. Like hundreds of kids at a ball game when they’re giving away tee-shirts. Then you see them. Flying in loose vees. Not soldierly, like geese. More like a family at the mall, changing from second to second, stragglers everywhere. Back in ancient Greece, it was thought that cranes form hieroglyphs—symbols—in the sky. The whisper of their wings, whomp, whomp, whomp, brushes by you, soft, but loud enough to hear from the ground. To me, they were the most beautiful, most majestic birds I have ever seen—sandhill cranes. Beginning in February and ending around the end of April, between 400,000 and 600,000 sandhill cranes congregate on the Platte River valley in Nebraska. They come from their winter grounds in Chihuahua, Mexico and in Texas, Arizona and New Mexico in the United States. They are in Nebraska to feed on the corn kernels left over by farmers after the corn was cut the previous fall. They are heading to the Arctic and just south of the arctic—on the Yukon and even into Siberia, in Russia—where they will spend 40-50 days nesting, laying their eggs and raising their babies. This migration has been taking place for millions of years. From research scientists have conducted, we know that sandhill cranes return to the same stretch of the Platte River each year. Thousands of people, like me come to see them in the Platte River Valley, because they are truly a spectacle. Cranes have been around more than 34 million years. Think about it. Most of the life forms that ever existed are now extinct—99% of them. But the cranes are still around. And they haven’t changed all that much. They are just about the same now as they were 10 million years ago! There is something about cranes that makes us love to watch them. Sandhill cranes are majestic. They are between three and four feet tall and the color of steel with a patch of read on their forehead. Their head often bobs and jabs as they move. The tips of their wings are black, when outstretched, the wingspan is more than five feet. When they move, they look like they are on stilts. Cool fact: Their knees serve as heels and they walk on their toes. On the Platte River valley, they feed on the left over corn, but they also like to eat insects, snails, frogs and even snakes! When they fly, they don’t use the even up and down motion of geese. Their rhythm is different. the down motion is twice as long as the up motion. The windpipe of sandhill cranes is shaped like a saxophone. Their neck, like you see in the pictures, is really long. Their calls carry for a mile. Sandhill cranes are named like horses. Males are roans, females are mares. Babies are called colts. They mate for life, and they communicate using sound and “dances.” Pairs often call at the same time. Roans point their beaks straight up in the air. Mares at a 45° angle. Her calls are higher pitched than his. She calls twice as fast as he does. When they roost in the evenings, during the nights and early mornings, they purr. It’s like the sound of a very gentle engine: rrrrrrr. During the day, they scatter over the cornfields near the Platte, in smaller groups. Sometimes a family group of three or four. Sometimes an extended group of 10 or twenty. Sometimes they group in the hundreds. Why do you think that would be? Maybe they found a particularly good field! In the fields you’ll see them eating, but if you’re lucky, you’ll see them dancing. You might even see them marching, all in a line, following a leader. Sandhill crane parents teach their chicks to dance. They teach them to bow. Chicks learn their moves for three years before they try to mate. Sandhill cranes are very wary of humans. Try to get close to them, the whole flock will fly off as if they were just one bird. They definitely communicate. For instance, a scout will go to a different location. That scout gives a call which lets the others know it’s safe to come. When I went to watch the sandhill cranes, I had hoped to see them dance (I did see them jump a bit) and get close to them. I stayed out late in the cold Nebraska evening, got up way before dawn to camp out by a river, all bundled up to wait for their taking off. We went from field to field during the day to see if we could catch some courtship displays. We didn’t see any dancing, and we never were able to get very close, but just being there, seeing wave after wave of black tipped red-headed cranes flying down to roost for the night in the near distance was magnificent. We were surrounded by their calls. We saw them arch their wings as they lowered themselves like ballerina’s into the river flats. We saw them, in the morning, take off in one group—it was over in seconds—the sights and sounds washing over us. It definitely was not disappointing. It just made me want to come back to Nebraska, for longer next time. Normally, when I write on this blog, I talk about scientists’ work. This blog I wrote about something I loved. One thing I want to point out, though, is that there are hundreds of volunteers in Nebraska who are doing all they can to keep the habitat for the sandhill cranes safe and healthy so that they will continue to be able to use that area as their feeding grounds for their long trip north. Check out the sounds I recorded during my visit with the cranes and some cool videos of cranes moving and dancing. I researched my information from these sources. “Flight Club,” an article in Smithsonian Magazine’s March 2014 issue By Alex Shoumatoff. http://www.nwf.org/Wildlife/Wildlife-Library/Birds/Sandhill-Crane.aspx http://animals.nationalgeographic.com/animals/birds/sandhill-crane/
A group is getting together at the lake nearby, and you want to tell your friends. But they are miles away. You phone or text, right? But what if you are an elephant?
How will an elephant communicate with other members of its herd? A human being cannot communicate without technology over miles and miles, but an elephant can. And the funny thing is that even if we humans were standing next to the elephant who is “calling,” we wouldn’t be able to hear it. Elephants rumble at a very low frequency. It is a frequency which humans can’t hear. We might be able to feel the air vibrating if we concentrate very hard, but the frequency in which elephants communicate over long distances is very, very low. It’s outside our range. It’s outside most animal’s range.
Elephants have big heads and because they have these big heads, they can have really long vocal folds, or vocal chords. Long vocal folds can vibrate quickly, if the elephants shorten them by using the muscles in their throat. They do this when they trumpet. The sound is high pitched, high frequency. The folds can vibrate slowly if they are not shortened. When the folds vibrate slowly, like when elephants rumble, the sound will be low pitched, low frequency. Scientists have proven that when one elephant rumbles, other elephants miles away respond and react. They can communicate over at least 4 kilometers, probably even over 10 km, which is a little over six miles.
Have you seen lightning and counted how many seconds it takes for the sound of the thunder clap to reach you? It’s supposed to tell you how far away the lightning strike was—five seconds for each mile of distance. Thunder rumbles at a low frequency and we hear it for miles. Elephants rumble at an even lower frequency, can you imagine how far they can hear each other?
Liz Rowland is a scientist who studies elephant communication to try to help the elephants be safe from poachers. Liz is a scientist for the Elephant Listening Project at Cornell University. The folks at the Elephant Listening Project figured out that elephants communicated in the really low frequency range by making recordings and speeding them up to frequencies humans can hear.
Now Liz and her co-workers have placed sound recording units in forest clearings where elephants get together. Many times these are places elephants visit to get mineral water. They use a spectrograph to turn sound into a picture. In the pictures they count the number of elephant calls and develop a database and graphs that tell them where the elephants are each day, what they do from season to season.
The reason for recording and analyzing the calls is that some elephants live deep in the African forests, and scientists don’t know a lot about them. When they know, from the recordings, where elephants meet, those areas can be protected from logging and from human disturbances. The scientists at the Elephant Listening Project have developed a way to figure out how many animals are at a particular location based on the number of calls recorded.
Recordings also allow scientists to keep track of poachers who kill elephants for the ivory in their tusks. The sound recording equipment has a gun shot detection feature which can be used to identify where shots were fired. Although it may be too late for that elephant, it may be possible to send patrols to catch the poachers and stop them from killing again.
Wouldn’t it be amazing if scientists were also able to tell which animal was making the call? They can’t tell just yet, but Liz and the other scientists can tell an older elephants (lower rumbles) from a younger one (higher rumbles). They have been able to determine that elephants recognize each other’s calls. Elephants can tell family members from non-family.
Other research that Liz and other scientists have done shows that elephants live in small family units—a mother an two or three young ones. They separate when daughters have their own families, but then they communicate and get together at gathering places. When they get together again, sisters stroke each other with their trunks, are they smelling each other? They are compassionate. They feel sorry for other family members and are tender toward them.
They are very sad when they lose a member of their group.
Liz works in a lab part of the time, but she also visits Africa to study the elephants. Isn’t that a job that you might want to have?
Would you bring dinosaurs back to life if you could? Cool idea, huh? Jack Horner is a paleontologist (a scientists who studies fossils). A professor at Montana State University, he is trying to do just that and he has had some success at it.
You may recognize Professor Horner even if you don’t know him. Dr. Alan Grant, one of the main characters in some of the Jurassic Park movies, was based on Professor Horner and his work. Professor Horner has helped make sure those movies, including Jurassic World, the newest one, are as scientifically correct as they can be. But his real job is a lot more exciting than that!
Professor Horner likes to find things. When he was a little boy, he loved dinosaurs; in fact, he wanted to have one as a pet. And he is dyslexic—reading is very difficult for him. Being a paleontologist was the dream job for him. He gets to find things, he gets to work with dinosaurs, and he can take his time with the reading he has to do. And he hasn’t found just any old dinosaur bones, he was the first to find dinosaur eggs in the Western Hemisphere—the half of the earth that includes North, Central and South America. He found the first nest of baby dinosaurs and a dinosaur embryo—a dinosaur that was mostly formed but hadn’t hatched yet. He was the first to find signs that perhaps dinosaurs cared for their babies. He is really interested in dinosaurs behavior toward each other—how social they are.
One of the projects on which Professor Horner is working now is trying to create a chickenosaurus. Is he trying to finally have his dream of having a pet dinosaur? Actually, the research that could lead to chickenosaurus, might also help human medicine some day. The techniques paleontologists are using to create chikenosaurus may help repair human beings some day. Read on and you’ll see how.
Not like Jurassic Park. In the movies, the paleontologists created the dinosaurs from the DNA in blood a mosquito sucked from a dinosaur at least 65 million years ago. DNA carries the instructions within an organism that makes it what it is. It’s what makes a giraffe a giraffe and a three-toed sloth a three-toed sloth and not a two toed sloth. It’s what makes you a human being different from your brother, your sister, or your friend. It also includes what each organism needs to develop, reproduce and survive. But it seems DNA can’t survive for millions of years. Scientists have found fossils, but they haven’t been able to find DNA yet.
But we don’t have to jump through hoops to get dinosaur DNA. We have it right under When dinosaurs evolved so that they could fly, the instructions that made the dinos hand changed so that a wing was made instead. The instructions that made tails turned off so tails didn’t grow. What Professor Horner and other paleontologists are trying to do is to reverse that evolution. To turn on the instructions—the genes—that made the hand instead of the wing and that made the tail grow.
Why a chicken? Why not? We know that sandhill cranes haven’t changed in 10 million years (blog to come soon on that). Hoatzins are birds that have claws at the ends of their fingers. Ostriches are very primitive birds, they can’t fly. They may all be closer to dinosaurs, but they are not small, domesticated and cheap to keep. Chickens have been studied because they are such a big part of our lives. Scientists have much more data on chickens than they do on the other birds.
What Professor Horner wants to do: He wants to create dino like a small velociraptor. To do that, he’ll need to change a chicken’s DNA so that it creates an arm with fingers and claws rather than a wing, a long tail, and a head without a beak and with teeth.
What has already happened: Scientists have already created chicken embryos with conical teeth, like the teeth of ancient crocodiles.
How this knowledge will help humans: What we learn about how genes create and develop an organism may help us understand how human bodies work and how it can be repaired.
Back to the original question: Would you bring a dinosaur back to life if you could? I don’t think I would. I definitely wouldn’t bring back any meat eaters—they might eat me. And the huge plant eaters would take up lots of food and space. No. I don’t believe I would want scientists to engineer any new animals or bring back old animals. I’m more of the type of person who thinks that we should do what we can to keep the animals we have. But…the research that Professor Horner is doing might help do just that. What do you think?
I got the information for this blog from a November 10, 2014 article in The Washington Post by Jackson Landers, a TED talk by Professor Horner, and the websites listed below. I have listed the Washington Post article so that you can access it if you would like. Phil Wilson, the artist who drew the sketch of what a chickenosaurus might look like, gave me permission to use his artwork on this website.
Washington Post Article:
Other websites: http://www.genome.gov/25520880
How can scientists go back in time, millions of years, to see what the earth was like? A time machine? You could think of it that way. Except these time machines pull up cylinders of ice or of sediment—particles of rocks, sand, shells, and anything that has settled—from the bottom of a lake, or an ocean.
Two scientists from the US Geologic Survey, Laura Gemery and Thomas Cronin, spent two months this summer in the Arctic Ocean, surrounded by nothing but open water, ice, a polar bear, and a walrus or two. They spent their tour on an ice breaker—the only kind of ship that can get through Arctic sea ice—pulling up sediment cores. It’s hard work. Heavy work. Sometimes it’s really cold work. It can still get down to -20° C considering the wind chill factor, in August and September!
Why do they do it? Laura and Tom are paleoclimatologists. They study climate—weather conditions for long periods of time—in ancient times. The sediment cores they pull up hold a record of what the earth was like hundreds, thousands, even millions and millions of years ago. Laura says that if we can learn what has happened on the earth through history, we’ll be better able to predict the climate of the future. When we know how climate may change, we can be prepared to respond to similar conditions.
Think about temperature, for an example. The temperature of the Arctic Ocean has changed over history. It has been as warm as 18 - 23° C (64-73° F). At that time, 55 million years ago, there were crocodiles in the Arctic Ocean. The level of the ocean was much higher. That means that during that period, which scientists call the Paleocene-Eocene Thermal Maximum (PETM), the ocean was much higher than it is today. The areas where cities like New York, Miami, Norfolk, San Francisco, San Diego lie today, were all under water. Lots of water. Other times, however, the temperature has been colder, the ice in the Arctic was very thick, and the level of the ocean has been much lower. The towns I mentioned above, would be totally safe and dry like they are now.
How do scientists get the cores? Corers are pushed into the sediment using gravity and weights. Each one of the cores can recover many meters of sediment. Since sediment collects at different rates during different times, these cores can represent tens, hundreds, thousands or millions of years. As the core barrels reach farther and farther down, they reach further down in history. Right now, scientists have sediment records back millions of years.
Laura says that they take the cores, which can be hard, like packed mud, or soft, like pudding, and cut them in half lengthwise. Then they have two “D” shaped lengths. One of the “D” shaped lengths of each core is stored as a permanent record. Scientists sample the other “D” shaped half. On this last trip, Laura took samples every 35 cm to see if they contained microfossils. She was looking for small crustaceans with two shells which are called ostracodes. She was also looking for foramnifera, organisms made up of a single cell. Ostracodes and foramnifera have shells that can be preserved, or become fossils when the conditions are right. Laura washed the samples through a sieve to remove very fine grains of sediment and separate the ostracodes and foramnifera.
So what do ostracodes and foramnifera shells tell Laura? Since there are many different species of ostracodes and foramnifera, let’s say Laura finds an ostracodes species that can only survive in water temperature between 20° C and 30° C. Now she has a very good idea—she can infer—that the water temperature at the time the sediment was laid down was in that same range. Since each species of ostracodes and foramnifera have different needs to survive, Laura can use them to predict certain environmental conditions such as the temperature of the water at the time the sediment was laid down. But Laura is not happy with just using the little foramnifera or ostracodes to peg a temperature to a period. She and colleagues use other methods to support their findings. The information they collect is put into a database that allows scientists to know what the climate was like at a specific place in the Arctic, at a specific time in history.
Temperature is not the only information sediment cores show us. Scientists also use the foramnifera and ostracode shells and the fossils of other organisms to determine how much salt there was in the ocean, how productive the oceans were (how much sea life there was) and how the currents in the ocean moved.
Who will use this? We can put together the temperature, salinity, and water current information with information we have about changing sea levels. Suppose you are an admiral in charge of a naval base in Norfolk, Virginia. You need to know what will happen to sea level in the future so you can prepare to move your ships. Building new docks takes many, many years. Or suppose you’re a fisherman. How will species in the Arctic change as the temperature warms, or salinity—the amount of salt in the water—changes? Or if you are the mayor of a town on the coast. You need to know what will happen to your town if sea levels rise.
We know that air and ocean temperatures in the Arctic and around the world are rising. We know that sea levels are rising. We know that ice is melting from glaciers (land ice) and there is not as much ice in the Arctic as there was before. Having the data that Laura and Tom compiled, along with many other scientists, will help us prepare to adjust to how our environment will change.
Do you think that when you’re old enough you’ll be willing to spend a couple of months in the Arctic, like Laura, to collect data to help us all be even more prepared as our climate changes?
Have you ever thought scientists might find a dinosaur bigger than Tyrannosaurus rex?
They have. Paleontologists—scientists who study fossils—have identified a dino which measured 50 feet. That’s 9 feet longer than any T. rex ever found. It was bigger than a bus. And what’s even more interesting, this big guy, Spinosaurus, lived and hunted in the water as well as on land. Before this discovery, paleontologists knew that some huge prehistoric reptiles, like crocodiles, lived in water. But no aquatic dinosaurs had been identified before.
This was not really a new dinosaur. About 100 years ago, in 1912, a bone and fossil collector, Richard Markgraf, found some bones—parts of ribs, a lower jaw, tail and vertebrae which were attached to large, flat, long spines. Ernst Stromer, a German paleontologist, examined the bones and saw that these fossils were different from any other dinosaur bones found before that time. Because the bones were different, he knew he had a new dino. But what kind of dino? And what should he call it?
The new dinosaur’s jaw was long and slender and had teeth good for catching fish. The scientist thought this new dinosaur was a gigantic predator that may have spent some time hunting in the rivers of North Africa. It probably fished by dipping its head in the shallows. The spines on the vertebrae that he found were likely to have formed a sail. Strommer called his new find, Spinosaurus. Because he had found it in Egypt, he called it Spinosaurus aegyptiacus.
Back in 1915, Strommer had an idea of what Spinosaurus might have been like, but not a good idea. He didn’t have enough bones to picture the giant. That changed in 2013. Then Nizar Ibrahim, another paleontologist, found a very large number of Spinosaurus bones. It turned out to be a young dinosaur—not fully grown—but it was already 36 feet long. Scientists determined that a full grown Spinosaurus would have been about 50 feet long, the largest predatory dinosaur found so far. Even bigger than the fearsome Tyrannosaurus. They knew that it had lived about 97 million years ago, in Africa. In an area full of other big predators.
How do paleontologists figure out what a bunch of bones might represent? It is like putting a puzzle together—being a detective and using clues. Putting the skeleton together is the puzzle part. They used bones they found from different Spinosaurs. They filled in missing parts by using what they know about other animals and dinosaurs.
They figured out how the dinosaur lived by comparing the bones to other animals’ bones. Spinosaurus bones were dense—thick and heavy— and compact, like the bones of penguins and whales—animals that spend most or all of their time in the water. The dense and compact bones help them stay in the water. The bones that formed the dinosaurs hips, were like the bones of other animals that had moved from land to water. The nostrils on its head were set back, closer to the eyes on the snout. This would have allowed Spinosaurus to breathe while keeping its head mostly under water—like crocs.
Have you ever seen a crocodile’s teeth? They are different from most animal’s teeth. They are conical and interlock. Guess what? Spinosaurus’ teeth are conical and interlock too. From this clue, paleontologists could tell that Spinosaurus would have eaten the same thing that some crocodiles eat—fish—huge fish. Another clue that they preyed on fish is the pits found on the jaw bones. The pits are holes that may have allowed the animal to know of movement of prey under water.
The new dino’s forelimbs had foot-long claws to tear meat. The arms were strong and large and the back legs were short, with paddle-like feet—both good for swimming. And more importantly, a dinosaur that large, with such small back legs, would not have been very good on land. It would have been slow. It would not have been able to stand on its back legs for long periods of time like T. rex. Instead, it probably walked on all fours—rather slow—while on land. A long and flexible tail, like a crocodiles’, might have helped push Spinosaurus through the water.
And what about the spines that give Spinosaurus its name? Scientists think the spines formed a sail. Maybe it allowed other dinos to see it while it was partially under water.
Now that you know the clues scientists used, can you see how the paleontologists think that Spinosaurus was the first semi aquatic dinosaur found? Do you like to solve puzzles? Maybe you would enjoy being a paleontologist. Check out the links below to see more pictures of the scary beast. If you live in the Washington, D.C. area, you can see a life-size model of the frightening Spinosaurus, the largest and the first aquatic dinosaur found. It’s on display outside the National Geographic Museum.
Here are the articles I read to write this blog post. You can find a really cool story about how the bones were found if you read some of these. Nizar Ibrahim, Ph.D., the paleontologist and National Geographic Explorer who analyzed the newest Spinosaurus bones, was unbelievably helpful to me in writing this blog. Clare Jones, also from National Geographic, helped me obtain the pictures you see here. Thank you to National Geographic for the use of these beautiful pictures.
Changspet, Kenneth. “A Lost-and-Found Nomad Helps Solve the Mystery of a Swimming Dinosaur.” http://www.nytimes.com/2014/09/12/science/a-nomads-find-helps-solve-the-mystery-of-the-spinosaurus.html?_r=0 Accessed September 17, 2014.
Joyce, Christopher. “Crocodile Meets Godzilla—A Swimming Dino bigger than T. Rex.” http://www.npr.org/2014/09/11/347488364/crocodile-meets-godzilla-a-swimming-dino-bigger-than-t-rex. Accessed September 17, 2014.
Mueller, Tom. “Mr. Big.” http://ngm.nationalgeographic.com/2014/10/spinosaurus/mueller-text. Accessed September 17, 2014.
Switek, Brian. “What Do We Know About Spinosaurs?” http://www.smithsonianmag.com/science-nature/what-do-we-know-about-spinosaurs-89178721/. Accessed September 18, 2014.
Thompson, Helen. “First Dinosaur Adapted for Swimming.” http://www.smithsonianmag.com/science-nature/meet-mighty-spinosaurus-first-swimming-dinosaur-180952679/?utm_source=smithsoniansciandnat&no-ist Accessed September 17, 2014.
Watson, Tracy. “New ‘Massive’ Dinosaur Skeleton Discovered.” http://www.usatoday.com/story/news/nation/2014/09/11/dinosaur-swimming-spinosaurus-skeleton/15448103/. Accessed on September 17, 2014.
What was Titanoboa? Can you tell from the name? Yes. It was some sort of snake. And it was huge. It lived 58 million years ago, about 6 million years after dinos became extinct. But it was almost as long as the height of T Rex. The first fossil of this monster was found in Cerrejón, Columbia, in South America, in 2003. But when they first saw the fossil, scientists didn’t quite know what kind of snake it had been.
The place where the fossil was found had been a swampy jungle. Now, it was a coal mine. Mining equipment had scraped off the top layers of soil. In 1994, a geologist found a fossil and thought it was a piece of petrified wood. In 2003 a Colombian geology student found many more plant fossils at the same place, but when other researchers joined the search, a Smithsonian scientist recognized that the “petrified branch” was actually a jaw bone of a dyrosaur, a very large dinosaur. Along with it, they found a hip bone. Now they knew that at Cerrejón they might also find animal fossils. Once the team knew about the animal fossils, they called in Jonathan Block, a paleontologist at the University of Florida. Bloch, his students and other paleontologists, traveled to Cerrejón to collect fossils. And what they found were all gigantic.
They found turtle shells more than five feet wide. Animals like crocodiles, but much, much bigger. Skeletons of lungfish, which now measure two to three feet, measured seven feet long. Over the years, animals had died. The mud in the Cerrejón swamp had preserved the layers of fossils, one on top of the other. When the coal mine began to operate, mining machines removed layers and layers of soil. Rain washed other muck away and fossils were exposed. It was like Christmas! Scientists found so many fossils that they’d bundle them up in plastic bags and bring them back to the United States to study them.
Alex Hastings and Jason Bourque, students at the University of Florida, were looking in a bag which was labeled “crocodile” when Alex found a huge vertebra—the bones that make up the spine of an animal. But this was not a crocodile bone. They knew it was the vertebra of a snake. Later scientists from the University of Florida returned to Cerrejón, and found vertebrae from 28 different snakes. One hundred fossil vertebrae in all. Eventually, they even found a snake skull. Using math to compare the size of a modern snake’s vertebra to its full length, and then applying that to the size of the Cerrejón vertebrae, paleontologists determined that Titanoboa had been between 42 and 49 feet long. It weighed about 2500 pounds—more than a ton—the same weight of a small rhino, or a small car. The snakes were so huge that if a man were standing next to one which was slithering on the ground, the snake’s body would be as tall as his waist. It could barely squeeze through a doorway. Gigantic!
But what kind of snake was it? Bloch and another paleontologist, Jason Head, could tell that the snake belonged either to the family of boas or to the family of anacondas. They knew it belonged to one of those two families because the vertebrae they found formed a T-shaped spine. Both the boa family and the anaconda family have T-shaped spines. But the bones looked more like the bones of other boas. They decided that it was a boa. In 2009, they named it Titanoboa.
Have you noticed something special about this discovery? Students played a part in it. And not just the ones mentioned here. Other American and Colombian students helped search for fossils at Cerrejón and then e-mailed the pictures to Bloch. Can you put yourself in those kids’ shoes? They’re older than you, but think about it. Even in college they were taking part in scientific discoveries. Is that something you might want to do?
I found my information in an article by Guy Gugliotta in Smithsonian Magazine. The article was published in April of 2012. Jonathan Bloch was very kind in answering my questions. I also consulted the following websites:
I obtained permission to use the pictures.
How do you live by the shadow of a volcano?
Is it scary to live close to a volcano? My human, Terry, thought it might be, of course, but she hadn’t really thought about it until she was invited to visit schools in the Mount St. Helens area.
Talking to students at Yale Elementary School and Woodland Intermediate School, Terry saw what it is for a young person to live in the shadow of a volcano. These schools are a few short miles from Mount St. Helens. If magma rises again into the mountain and Mount St. Helens erupts, the students in these schools when the mountain erupts will feel its effect.
Terry has done many school visits in her home state of Virginia, in North Carolina, in New Jersey. To students in these areas, Mount St. Helens, or any volcano, is something far away. Interesting, but not threatening. She might get a question about whether Mount St. Helens will erupt again, but that’s not very often. But close to Mount St. Helens, that was the first question she got. When will it erupt again, and what will happen? It seemed that every student she talked to had a jar of Mount St. Helens ash that their parents or grandparents had collected after the eruption.
The good thing about volcanoes is that they give warnings—earthquakes. Mount St. Helens was shaken by earthquakes for fifty-nine days before the mountain’s huge eruption. At first the earthquakes were smallish, then earthquakes became more frequent, sometimes earthquakes shook the mountain about once a minute. Scientists knew the mountain was closer to erupting when the earthquakes became rhythmic—that meant that magma was really on the move—and when a bulge started growing on the side of the mountain. These were all signs that everyone could feel. They could also see small eruptions of ash and steam from a crater that formed a couple of days after the first earthquake. Scientists placed seismographs all over Mount St. Helens and the other volcanoes in that area. These seismographs will get the earliest warning signs.
Terry and Abi Groskopf, a scientist from the Mount St. Helens Institute, told the students about the earthquakes, and about seismographs. Abi also told the students that the last big eruption, in May 18, 1980, had blasted out to the south, away from the schools they were visiting. The important thing about volcanoes is that, when there are warnings, they need to be obeyed.
Sometimes it’s hard to believe that the danger is real. It took fifty-nine days of rocking and rolling for Mount St. Helens to finally erupt. The mountain was closed, of course. People were urged to evacuate. But as days came and went and the mountain didn’t erupt, people began to think that Mount St. Helens was not going to do it. A group of people that owned vacation homes in the Mount St. Helens area talked the governor into letting them go into the evacuated area to pick up their valuables on the day before the eruption. A second group was supposed to go mid-morning on May 18th. The mountain erupted at 8:32 in the morning. Do you think it was smart for those people to want to go back to the mountain to get their valuables? They could have lost their lives!
Some people chose to stay on the mountain. Harry Truman, an 83-year-old gentleman named after our 33rd president, owned an inn on Spirit Lake at the bottom of the mountain. He chose to stay. He died. People went around the barricades that the Forest Service had placed to watch the volcano and be there if it erupted. Some of those people died. Many had harrowing experiences. Even a scientist from the United States Geologic Survey(USGS) was killed. David Johnston was at the USGS observatory six miles away from the mountain, at a place scientists felt was safe, and he was killed by the blast. A photographer from a newspaper in the area was also killed. He was about eight miles away.
Giving so much warning, and being in an area that is easy to access, Mount St. Helens taught scientists lessons about eruptions. It taught that volcanoes can erupt laterally, straight ahead, as well as erupting up. Scientists had seen rock patterns around other volcanoes that they couldn’t explain. Now, seeing that Mount St. Helens erupted laterally, they had an explanation for those rock patterns. Since Mount St. Helens was turned into a National Monument, and the recovery of the mountain is being studied, scientists have learned many other valuable lessons. Of course, the lesson they learned that Terry likes the most is the one about the gopher helping in the recovery. That’s the one she wrote about in Gopher to the Rescue! A Volcano Recovery Story.
How would you feel if you live in the shadow of a volcano? Maybe you do. You might want to write a story comparing and contrasting the reasons why you would want to stay and the reasons why you absolutely need to go. Find out which volcanoes in the United States are active. Can you figure out a reason why all those volcanoes are in about the same area? What is that area called? Next time, we’ll talk more about those volcanoes. Stay tuned.