Science Made Cool

Flying Fish, Sort Of

A fish out of water flops – everyone knows that. But while most fish flail in place when they’ve got no water to push on, a few species can flip into a controlled long jump that sends them flying several times their body length in one direction. How far can these fish jump? Take a look at this mosquitofish (Gambusia affinis) in flight.

http://jan.ucc.nau.edu/acg/video/Gambusia_affinis/Gambusia_affinis.mov

Pretty cool, eh? Understanding that jump is the subject of a paper published today in the Journal of Experimental Zoology by Alice Gibb, Miriam Ashley-Ross, Cinnamon Pace, and my former grad school officemate John Long. They noticed that these jumps looked a lot like the movements a swimming fish makes to escape predators _­– called a “c-start” for the characteristic letter-shape the fish bends into – and they figured that the fish were co-opting their aquatic escape behavior for moving efficiently on land. But when they looked more closely, they found that there were some important differences.

                    

For one, on land, the fish don’t bend their tail and head toward the middle of the body evenly as they would in a watery c-start. Instead, they swing head toward tail, bending the body in a sharp curve before a push from the tail launches the fish into the air. The difference seems small, but it implies that the fish are using the same set of muscles differently on land and underwater. So if one of these fish gets stranded on land, the same muscles that produce a rapid-fire snap-and-dart in the water can shift to a slower rhythm that gives the fish a better chance of getting back in the water. 

Research paper: Gibb AC, Ashley-Ross MA, Pace CM, Long JH Jr. 2011. Fish out of water: terrestrial jumping by fully aquatic fishes. J. Exp. Zool. 313A: DOI 10.1002/jez.711

(And more videos at http://jan.ucc.nau.edu/acg/video.html)

 

Toady Went A-Hunting

Remember yesterday’s movie of the toad eating in slow motion? Now watch this one. It’s still a toad eating a cricket, but this time it was filmed at two different temperatures. Keep two things in mind – first, the toad’s body temperature is the same as the air around it, and second, muscle works faster when it’s warm. That’s why it takes a lot longer for the toad to pull its tongue into its mouth and close its mouth at 17°C than at 24°C. But there’s no real difference in the time it takes to for the toad to fling its tongue out of its mouth. That’s because tongue extension is powered by elastic recoil. Slow muscle contractions pull elastic tissues inside the tongue tight while the toad’s mouth is still closed. When it opens, the tongue flies forward like an arrow from a bow. So whether it's hot or cold, the toad's always ready to go hunting. 

Deban, S. M. and A. K. Lappin 2010. Thermal effects on the dynamics and motor control of ballistic prey capture in toads: maintaining high performance at low temperature. J. Exp. Biol. 214: 1333-1346.

Video by Stephen Deban.

High-Speed Dining for Toads

There's lots of interesting biomechanics going on in this short high-speed video of a toad eating a cricket. For example, watch the tongue elongate from its own inertia as it whips out of the toad's mouth. And see how the toad's eyes start to close as it swallows the cricket at the end of the film? That's not satisfaction -- it's using its eyes to help shove the food down its throat.

For details, see

Lappin, A. K., Monroy, J. A., Pilarski, J. Q., Zepnewski, E. D., Pierotti, D. J. and Nishikawa, K. C. (2006). Storage and recovery of elastic potential energy powers ballistic prey capture in toads. J. Exp. Biol. 209, 2535-2553.

Levine, R. P., J. A. Monroy and E. L. Brainerd 2004.Contribution of eye retraction to swallowing performance in the northern leopard frog, Rana pipiens. J. Exp. Biol. 207: 1361-1368.

 

Video by Stephen Deban and Kristopher Lappin.

19th Century Bone Wars on the American Experience

A few years ago, we designed a card game inspired by the outrageous antics of 19th century American paleontologists. This week, WGBH's debuts a new documentary on the same subject: you can watch Dinosaur Wars when your local PBS affiliate broadcasts it later this week, or stream it right now on the American Experience website. Clearly, scientists behaving badly are a great subject for drama.

Spider Predation + Talented Animators = Awesome

From the animation company Polynoid, a five minute film of a spider catching a meal. Hyperrealistic art, except when it's illustrating silk formation -- then it shades into abstract shapes, which might seem a little weird, but it's not like you can see down there at the molecular level.

 

Loom from Polynoid on Vimeo.

 (h/t Eric Mead)

What Happens When an Elephant Dies?

The answer's simple: other animals eat it. As part of an upcoming documentary film, Channel 4 filmed an elephant carcass in Tsavo West National Park (Kenya) for a week as scavengers reduced it to a pile of bones.  

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h/t to Mary Roach! (She always finds the best stuff...)

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Neural Interface? Check.

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Mr. Stark, please call your office. You've suddenly ceased being a fictional character.

Faster than the Eye can See: Flying with a Snap

On any ordinary day, a trap jaw ant uses its hair-trigger mandibles for pretty much the task you’d expect of a predator – catching prey before it realizes it's in any danger. But sometimes even the most ferocious predator has to run away. And if you’re small, light, and happen to have jaws that can snap shut at nearly 140 miles per hour, you have an option that’s far faster than your legs can carry you. Simply snap your jaws against a hard surface, and the reaction force will send you flying. 

Sheila Patek (now at the University of Massachusetts, Amherst) captured the ants flight on high-speed video, filming at 3000 frames per second.

Faster than the Eye Can See: Quick as Lightning

The clouds roll in, the sky darkens.... and a flash of light in the sky tells you it's time to find some cover. Whether you see it as a flash in your peripheral vision or as a long bolt joining sky and ground, lightning strikes happen so quickly that our brains can only register the grossest outlines of the phenomenon. The actual complexity of lightning is only revealed with high-speed video.

Here's an example. Tom Warner caught a set of lightning strikes with a high speed video camera at 9000 frames per second, slowing what would seem like a simple flickering bolt in realtime into a complex dance of electricity.

Cephalopod Awareness Days: Striking in the Blink of an Eye

While others turn their prose towards ‘pods like the giant octopus or the flashy nautilus, I’d like to take a moment to appreciate the small, unobtrusive, dirt-common, Long-Finned squid (Loligo pealei). They live fast – reaching adulthood, spawning, and dying in less than a year – and can tolerate a wide range of water conditions. They’re the lab rat of cephalopods: their giant axons have been instrumental in working out how nerve cells work. They can also snag a shrimp out of the water column in a fraction of a second. Now you see food, now you don’t. 

The food-nabbing speed comes from a pair of long, thin hunting tentacles held inside the squid’s eight shorter arms. When the hungry squid spies a shrimp, it turns to face it, points its arms toward the prey, then splays its arms open and shoots its tentacles forward with lightning speed. Within 30 milliseconds, the shrimp is stuck on the tentacle’s suckers and is getting pulled toward the squid's waiting mouth.

  

120 milliseconds of a squid catching a shrimp. (From Kier and Van Leeuwen, 1997)

The tentacles are fast because they’re long and thin. In your arm, bones act as levers and muscles pull them to and fro. Squid are boneless, relying instead on muscles arranged in patterns that oppose one another. When muscles running around the outer edge of each tentacle contract, the entire tentacle gets longer and narrower – and since the squid is already sitting at one end, the shape change shoots the shrimp-catching ends of the tentacle forward. 

 

Reference: Kier, W. M. and J. L. Van Leeuwen 1997. A kinematic analysis of tentacle extension in the squid Loligo pealei. J. exp. Biol. 200: 41-53.