Jump In Jerboas!
The jerboa is a member of the rodent family, but looks like “a fuzzy rodent T-Rex” according to scientists studying the animal’s long, springy hindlimb. Video producer Christian Baker tells us how the jerboa’s elongated back leg can clue us in to the evolution of our own bones.
Luke Groskin is Science Friday’s video producer. He’s on a mission to make you love spiders and other odd creatures.
IRA FLATOW: Next up, a sci-fry Christmas tale. T’was the night before Christmas, and all through the house, not a creature was stirring, not even a jerboa. Yes, jerboa, I said. Yeah, our next story is not about a mouse but its floppy-eared, long-footed cousin, the jerboa.
You say you never heard of a jerboa? Well, that’s the subject of our latest macroscope video. My next guest is here to tell us all about it. Christian Baker is a video producer based in Los Angeles. You can watch his new video on our website, sciencefriday.com. Welcome, Christian.
CHRISTIAN BAKER: Hi, Ira, how’s it goin’?
IRA FLATOW: Were you familiar with jerboas? Tell us what a jerboa is.
CHRISTIAN BAKER: I was not familiar with the jerboa. I had never seen them before. But they are very familiar looking. They look very similar to a mouse. They have the same basic body structure. But whereas a mouse is quadruped walking around on all four limbs, the jerboa is very noticeably bipedal, because it has these very crazy, springy hind legs. You can’t miss them.
IRA FLATOW: So it’s like a kangaroo crossed with a mouse.
CHRISTIAN BAKER: Yes. It’s been described in many ways. I like, in particular, a potato with toothpicks, or a furry rodent version of a Tyrannosaurus Rex.
IRA FLATOW: I’m Ira Flatow. This is “Science Friday,” from PRI, Public Radio International, talking about jerboa with Christian Baker.
The hind limbs of the jerboa are really long, almost the entire length of its body. And you describe it, as you say, looking sort of like a T-Rex– a tiny T-Rex. Why does it need such big back legs?
CHRISTIAN BAKER: Well, it’s interesting, because jerboa are found in Asia and Africa and like, the desert regions. And they, over millions of years, have developed these hind legs to help them evade predators. Because if you’re out in the desert areas, there’s not a lot of cover to hide under.
So as these jerboa are kind of scurrying around looking for food, a bird of prey, say, swoops in and tries to snatch one up– if it was to do that with a mouse, the mouse doesn’t have a lot of means to escape. It’s kind of stuck in a two-dimensional space.
IRA FLATOW: So this can jump pretty well, then?
CHRISTIAN BAKER: Yes, absolutely. The jerboas can kind of use their springy legs to jump really high. They can reach about three feet, straight up in the air.
IRA FLATOW: Wow.
CHRISTIAN BAKER: Which is very impressive.
IRA FLATOW: It looks like they’re bouncing around on a tiny foot when you look at them, but that’s actually their toe, right?
CHRISTIAN BAKER: That is correct. They walk upright on their toes. Their legs are really kind of weird looking.
If you were to see the video, what you’re looking at is– when you look at their legs, what you think is a backwards-turned knee is actually their ankle. And then this very long bone that shoots out from that you would think is their shin bone, but that’s actually their foot. And then connected to that are their toes. And that’s what they walk around on.
IRA FLATOW: Now, you filmed a few hopping jerboas for your video. Were you actually able to pick one up? I mean, are easier? Do they just jump around so much?
CHRISTIAN BAKER: Not only was I not able to pick one up, it was very difficult to even film them. They are really quick. We had set up a little enclosure, and we were trying to film them. I think I was on my belly for about 45 minutes panning the camera left and right, and we certainly have a lot of very blurry footage. It’s probably similar to pictures of the Loch Ness.
But when it came to actually trying to wrangle them and pick them up, I left that up to the professionals.
IRA FLATOW: Yeah. Yeah, don’t want to get involved. Kim Cooper, this scientist speaking to professionals featured in your video, is studying the evolution of the jerboas’ hind limbs. What question is she trying to figure out?
CHRISTIAN BAKER: So Kim Cooper wanted to study developmental science. And she chose the jerboa because it’s small, it’s cute, and it has these crazy springy hind legs. What she wanted to know was how it developed these hind limbs that are both radically different from that of a mouse but also radically different from its two front legs.
Now, if you were to think of it this way, the bones in our fingers are the same material that are made up of the bones in our legs. So your pinkie bone is basically the same stuff that’s in your femur. So how does each know to grow to be a different size and to grow at a different rate? So this was kind of a question that she started to find as she was researching and studying the jerboa.
IRA FLATOW: Anything we can learn– you compared some of the bones to our fingers– anything we can learn about us from studying the jerboa?
CHRISTIAN BAKER: Absolutely. So what we can learn by studying the growth rate of the bones in jerboas is how those bones grow as fast and as large as they do. And if we can understand the mechanism behind that, then we can understand– we can start to understand– how to manipulate that mechanism, which has applications if you are trying to treat bone growth deficiencies in people.
IRA FLATOW: And after people see your video, they’re going to say, oh, these are cute little animals. I want to take one home with me. This is not the kind of animal that’s going to make a cute pet, is it?
CHRISTIAN BAKER: They are, unfortunately, illegal to own as pets in the United States. And that was the very first thing I looked into. But it is sad to say, you cannot own one.
IRA FLATOW: Well, you have to catch one first.
CHRISTIAN BAKER: Yes.
IRA FLATOW: Can’t catch it. And was this one of the toughest shoots you had to do, ’cause of not being able to get really that close to the animal?
CHRISTIAN BAKER: Well, it’s funny, because you are able to get– I was able to get close to them, or rather, you let them come up to you. But it was certainly one of the most difficult subjects I’ve ever had to film.
IRA FLATOW: And there you have it. Christian, thank you for joining us.
CHRISTIAN BAKER: Thank you, Ira.
IRA FLATOW: And have a happy holiday season to you. Christian Baker is a freelance video producer based out of Los Angeles. And you can see Christian’s video about the jerboa, this cute little animal, on our website at sciencefriday.com.