Secret to Clingfish Suction Power Found

Using tiny hairs similar to those on gecko feet, clingfish are able to strongly and equally adhere to surfaces with a broad range of roughness, new research shows. The fish's suction powers easily outperform manmade suction cups, scientists say, adding that mimicking their design could lead to a new class of suction devices. 

The northern clingfish (Gobiesox maeandricus) is a species of salt-water fish native to the Pacific Coast of North America. The fish live in rocky intertidal environments, where strong waves and currents threaten to toss them about. To survive in this turbulent setting, the fish has evolved an adhesion disc on its belly, which takes up about 25 percent of its underside. Using the disc, the fish can achieve a death-grip on a variety of surfaces. 

"Basically, if they get stuck on a surface, you are going to have to really yank on them to get them off," said study researcher Adam Summers, a biologist at the University of Washington. "And if you throw them in a bucket with water and then dump it out, you'll have an empty bucket with nothing but the clingfish inside." [Image Gallery: Freaky Fish] 

Suction power 

Summers and his colleagues wondered how clingfish could rapidly stick to, and release from, surfaces of arbitrary roughness, and how they compare with manmade suction cups. To test this, the team made epoxy molds of "every kind of sandpaper you can imagine," from the finest sandpaper to those rough enough to strip finish from flooring. They put these molded surfaces into a tank filled with water. 

Continued: http://www.livescience.com/29233-clingfish-suction-adhesion.html

Sucking salamander uses jaw power to bend prey

11:33 6 March 2013

Giant salamanders can handle prey larger than their mouths. As shown in this video, the amphibian can make a long roach bend into its open jaws by the power of suction alone.

Egon Heiss from the University of Antwerp, Balgium, and colleagues captured the clip to better understand the mechanism, of which little is known. Compared with fish - which suck up prey by drawing in water that's later expelled through their gills - salamanders release water back through their mouths again.

A fluid dynamics model, shown in the second part of the video, uses CT scans and high-speed videos to mimic the action. "It proves that only the fast separation of the jaws generates the high fluid velocities, as no other movements of the salamander were simulated," says Heiss. After the initial jaw opening, a bony structure at the back of the mouth, which in fish is responsible for sucking, also moves, but the model shows that this motion isn't involved in prey capture. Instead, it seems to maintain flow.

The team thinks that the changeover to jaw-powered suction could have been important in the evolution of terrestrial life. "This could have opened the path for further modifications, such as the evolution of a fleshy tongue, without losing performance as aquatic predators," write the team.

If you enjoyed this post, watch a hagfish get slurped up in the first video of a deep-sea seal hunt or see how a snail's spiral shell can save it from the jaws of a snake.

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