Lindsey Swierk/Macy Petrula/Patricia Esquete/ Ethology
ANIMALS – For a frog or other amphibian animal (like a hippopotamus), going from dry land to water is a piece of cake. For these animals, running away in the water and hiding for a long time from predators is the norm. In spiders, on the other hand, this is an unusual technique.
Yet this is what a newly discovered species, the Trechalea extensa, which has more than one trick up its sleeve. In a new article published in the journal Ethology, researchers present this new species measuring 2.4 cm in length and 14.1 cm when its legs are extended. We discover in particular their trick to survive temporarily under water.
In general, spiders do not like being submerged. Because it is not their habitat, they find themselves in particular unable to breathe. But this tropical spider has found the solution, using its hydrophobic fur to build air armor.
Armor made of air and hair
They are therefore not afraid of water, even if the study specifies that these animals “are rarely known to submerge, whereas their aquatic prey is normally accessible by land.” Besides, the reason this new species goes diving is not hunting. The predator sometimes becomes the prey, and it is to defend itself that Trechalea extensa flee under water. And it’s not a simple dip, since these arachnids can immerse themselves for more than 30 minutes!
To achieve this feat, these spiders need air, but also to compensate for the loss of heat caused by the change of environment. This is where the superpower comes in. Equipped with a layer of fur over its entire body as shown in the photo below, the latter is hydrophobic.
“The film of air surrounding the spider when underwater appears to be held in place by hydrophobic hairs covering the entire surface of the spider’s body,” says one of the study’s authors, Lindsey Swierk. The researcher also adds that this armor of air and hair is “so complete that the spider almost looks as if it has been dipped in silver”.
This mechanism could also help minimize heat loss caused by the cold water in which the spider immerses itself Lindsey Swierk remarks: “For many species, getting wet and cold is almost as risky for survival as facing to their predators to begin with”.
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