AMNH
AMNH

Michael Habib, Pterosaur Flight Expert

AMNH
AMNH

The American Museum of Natural History's latest exhibition, Pterosaurs: Flight in the Age of Dinosaurs, opens today (check out just a few of the things we learned at the exhibit here). At the media preview, we spoke with pterosaur flight expert Dr. Michael Habib about figuring out how these reptiles flew.

When you and other scientists are trying to figure out how pterosaurs flew, do you start with the fossils? Or do you start with an animal alive today because we know the flight mechanics and work backward?

We do a little bit of both. Mostly, you start with fossils. Then you go to the principles of physics—things that are fundamentals that you know are true, because physical laws make them true and they're going to be true for everything. Then you build models from that and validate them using the living things: Does the model make good predictions in birds? Does it make good predictions in bats? If it does, I'm relatively confident that it will make good predictions in pterosaurs.

The trick, of course, is the predictions all have to do with anatomy, and make predictions about the anatomy. To say, "Alright, if this hypothesis is true, then it would look like this and if it was false, it would not look like this." And then you test to see if that is what the anatomy looks like in the animals you have. That's kinda tricky, and part of what you do to make it reasonable, is you pick the tractable questions and tractable approaches. An intractable question for pterosaur flight is "Exactly how fast does a Quetzalcoatlus fly?" And a tractable question is, "Would quetzalcoatlus fly faster or slower than a living large bird?" Comparable questions are more tractable than absolutes.

That question is actually not completely intractable. I can get a good idea of how fast it could probably fly. But I couldn't give you an absolute answer because we don't know exactly what the wing shape was on the animal. So actually the answer would be—it would vary. Flying animals change their speed based on how much fat they've burned on that long trip, for example. They start off as a big fat bird and show up as a little skinny bird. So there is no single answer to that anyway. But I can give you an idea of range. What I can say with more confidence is how pterosaurs would fly relative to certain first principle models and relative living animals.

Pterosaurs came in a huge array of sizes. How would you say the 10 inch little guy, Nemicolopterus cryptus, flies compared to something bigger like Quetzalcoatlus?

Small things tend to be more maneuverable. They fly slowly in terms of mass of speed, but they tend to be more maneuverable. And landing and takeoff is less energetic for them. In this particular case, the animal is not just smaller, it also has other wing characteristics that are associated with highly maneuverable flights, so it would be less efficient but more maneuverable. Quetzalcoatlus would be a faster flyer, overall, because it's so much larger. It would probably be a flat glider that would flap in bursts and they would glide for long periods; it would probably be a soaring animal. Soaring is what we call it when you have an external source of lift—you're gliding, but you're not dropping relative to the ground because you've got some rising air, which is your source of external lift. Quetzalcoatlus probably hunted on the ground and flew between places to eat or escape predators or things like that. 

Would there be differences in take off and landing, too, depending on the animal's size?

We have some good ideas. Take off is sort of my specialty. It turns out that in all fliers—including unpowerfliers like gliding snakes, for example, even flying squirrels, things like that—in all the ones we've measured, launch is effectively ballistic. So the launch is not initiated with the wings. You don't flap yourself into the air, you jump yourself into the air. And then you engage your wings. Now, we don't see that. It's so fast. What it looks like to us is that a pigeon is pulling himself into the air with his wings, but he's actually pushing his feet and then pulling himself higher with his wings. Which might seem like a nitpick, but in terms of physics, it is fundamentally different.

Some animals run into the jump—especially on water; that's mostly where you see them running—some just jump. For pterosaurs, we're fairly certain they would leap as well. Since they walked on both feet and hands, the expectation is that they would probably leap with all four limbs—we call it a quadripedic launch. I have not run the test for all known pterosaurs by any stretch of the imagination. For all the ones I have done analysis on, it appears that that is true, so I would expect small and large ones use quadripedic launch.

That said, a little guy has a much larger room for error than a big one in the sense of, it doesn't have to put as much "oomf" into it. It could, from a power perspective, maybe launch bipedally, but there's no reason to think that it would. A small pterosaur wouldn't have to leap nearly as hard [as a big one] before it could engage its wings. It would probably get relatively much higher, launch more vertically, if it wanted, when it took off.

Big guys would have to launch at a much more shallow angle. That means they need some clearing in front of them in order to take off, which limits their habitat a little bit, and they're going to have to devote a lot of their muscle power to launch, which means you would expect those animals—as per the predictions I’ve mentioned before—if this model were true, you'd expect that there'd be certain anatomical features related to launch that would be exaggerated in big pterosaurs that wouldn't be in small ones. And that seems to hold true. Big pterosaurs are devoting more of their anatomy to that initial takeoff phase because it's a more rigorous phase for them.

What kind of computer programs are you using to model pterosaur flight?

For me personally, I do a lot of my stuff on a Matlab. It's the big bruiser on the market, but it's flexible. The equations it collapses through are surprisingly simple structures. The best expressions are the ones that are as simple as possible. I spend most of my time on a white board, quite frankly.

There's another Jurassic Park movie coming out. What would you want the director to get right about the pterosaurs in that movies if they include them?

Take off is my personal bias. Might as well see if they get that right. And it would actually be kind of embarrassing if they didn't, because they’ve done TV shows and gotten it right. So if Jurassic Park 4 didn't get it right, that would be embarrassing.

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These Sparrows Have Been Singing the Same Songs for 1500 Years
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iStock

Swamp sparrows are creatures of habit—so much so that they’ve been chirping out the same few tunes for more than 1500 years, Science magazine reports.

These findings, published in the journal Nature Communications, resulted from an analysis of the songs of 615 adult male swamp sparrows found in six different areas of the northeastern U.S. Researchers learned that young swamp sparrows pick up these songs from the adults around them and are able to mimic the notes with astounding accuracy.

Here’s what one of their songs sounds like:

“We were able to show that swamp sparrows very rarely make mistakes when they learn their songs, and they don't just learn songs at random; they pick up commoner songs rather than rarer songs,” Robert Lachlan, a biologist at London’s Queen Mary University and the study’s lead author, tells National Geographic.

Put differently, the birds don’t mimic every song their elders crank out. Instead, they memorize the ones they hear most often, and scientists say this form of “conformist bias” was previously thought to be a uniquely human behavior.

Using acoustic analysis software, researchers broke down each individual note of the sparrows’ songs—160 different syllables in total—and discovered that only 2 percent of sparrows deviated from the norm. They then used a statistical method to determine how the songs would have evolved over time. With recordings from 2009 and the 1970s, they were able to estimate that the oldest swamp sparrow songs date back 1537 years on average.

The swamp sparrow’s dedication to accuracy sets the species apart from other songbirds, according to researchers. “Among songbirds, it is clear that some species of birds learn precisely, such as swamp sparrows, while others rarely learn all parts of a demonstrator’s song precisely,” they write.

According to the Audubon Guide to North American Birds, swamp sparrows are similar to other sparrows, like the Lincoln’s sparrow, song sparrow, and chipping sparrow. They’re frequently found in marshes throughout the Northeast and Midwest, as well as much of Canada. They’re known for their piercing call notes and may respond to birders who make loud squeaking sounds in their habitat.

[h/t Science magazine]

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5 Fascinating Facts About Koko the Gorilla
ZUMA Press, Inc., Alamy
ZUMA Press, Inc., Alamy

After 46 years of learning, making new friends, and challenging ideas about language, Koko the gorilla died in her sleep at her home at the Gorilla Foundation in Woodside, California on June 21, 2018. Koko first gained recognition in the late 1970s for her ability to use sign language, but it was her friendly personality that made her a beloved icon. Here are five facts you should know about the history-making ape.

1. SHE KNEW OVER 1000 SIGNS.

Francine "Penny" Patterson, then a graduate student at Stanford University, was looking for an animal subject for her inter-species animal communication experiment in the early 1970s when she found a baby gorilla at the San Francisco Zoo. Originally named Hanabiko (Japanese for "fireworks child," a reference to her Fourth of July birthdate), Koko took to signing quickly. Some of the first words Koko learned in "Gorilla Sign Language," Patterson's modified version of American Sign Language, were "food," "drink," and "more." She followed a similar trajectory as a human toddler, learning the bulk of her words between ages 2.5 and 4.5. Eventually Koko would come to know over 1000 signs and understand about 2000 words spoken to her in English. Though she never got a grasp on grammar or syntax, she was able to express complex ideas, like sadness when watching a sad movie and her desire to have a baby.

2. SHE CHANGED WHAT WE KNEW ABOUT LANGUAGE.

Not only did Koko use language to communicate—she also used it in a way that was once only thought possible in humans. Her caretakers have reported her signing about objects that weren't in the room, recalling memories, and even commenting on language itself. Her vocabulary was on par with that of a 3-year-old child.

3. SHE WASN'T THE ONLY APE WHO SIGNED.

Koko was the most famous great ape who knew sign language, but she wasn't alone. Michael, a male gorilla who lived with Koko at the Gorilla Foundation from 1976 until his death in 2000, learned over 500 signs with help from Koko and Patterson. He was even able to express the memory of his mother being killed by poachers when he was a baby. Other non-human primates have also shown they're capable of learning sign language, like Washoe the chimpanzee and Chantek the orangutan.

4. SHE HAD FAMOUS FRIENDS.

Koko received many visitors during her lifetime, including some celebrities. When Robin Williams came to her home in Woodside, California in 2001, the two bonded right away, with Williams tickling the gorilla and Koko trying on his glasses. But perhaps her most famous celebrity encounter came when Mr. Rogers paid her a visit in 1999. She immediately recognized him as the star of one of her favorite shows, Mister Rogers' Neighborhood, and greeted him by helping him take off his shoes like he did at the start of every episode.

5. SHE WAS A LOVING CAT MOM.

Koko was never able to have offspring of her own, but she did adopt several cats. After asking for a kitten, she was allowed to pick one from a litter for her birthday in 1985. She named the gray-and-white cat "All Ball" and handled it gently as if it were her real baby, even trying to nurse it. She had recently received two new kittens for her 44th birthday named Ms. Gray and Ms. Black.

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