Watch caterpillars race on the water! | Earth


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Lizards are famous for their acrobatic feats on land and in the air, but a new study reveals that they too can run in the water.

Robert Full, professor of integrative biology at the University of California, Berkeley, is the senior author of the study, published December 6, 2018, in the peer-reviewed journal Current biology Full said in a statement:

They can climb a wall at one meter per second, they can glide, they can straighten up in the air with a twist of their tail and flip quickly under a leaf running at full speed. And now they can run a meter per second over the water. Nothing else can do that; Geckos are superheroes.

A gecko running through the water supported by paddling and surface tension. Image va Pauline Jennings / PolyPEDAL Lab, UC Berkeley.

The teams studied flat-tailed geckos, common in southern and southeastern Asia. In the laboratory, the research team built a long tank of water, placed the geckos on a board and surprised them by touching their tails. Using high-speed video, they were able to study closely the techniques of geckos and estimate the forces involved.

They found that geckos were able to run at about three feet per second over water, and easily transition to accelerate on terra firma or climb a vertical surface. Researchers said that geckos running on the water surface exceed the absolute swimming speeds of many aquatic specialists, including ducks, minks, musk rats, marine iguanas and juvenile alligators, and are faster at relative speed than any registered surface swimmer , in addition to whirligig beetles.

The study describes four separate strategies that lizards use to glide along the surface of the water: flattening, like a boat; surface tension support; hitting and dragging the water; and propulsion with the tail. Image via lab chart PolyPEDAL, UC Berkeley

Smaller animals, such as insects – spiders, beetles and aquatic insects, for example – are light enough to be kept afloat by surface tension, the researchers said, allowing them to glide easily across the surface. Larger animals, such as swans during takeoff or the basilisk lizard, and even dolphins rising on their tails, quickly beat and caress the water to stay above the waves. Full said:

Larger animals can not use surface tension, so they end up pushing and hitting the surface, which produces a force if you do it with enough force.

But the lizard is intermediate in size: about 6 grams (1/5 of an ounce, or the weight of a sheet of paper), they are too large to float above the surface, but too light to keep their bodies above the surface. Water. beating only the forces.

Animals use a variety of techniques to stay above water. Lighter animals, mainly insects, are sustained only by surface tension. Heavier animals can produce enough force with their feet or tails to stay above water. But the lizards are in the middle, using both techniques. Image via lab chart PolyPEDAL, UC Berkeley

Bottom line: A video shows geckos running in the water.

Source: Geckos Race across the water surface using various mechanisms

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