Why do water birds survive the rain – Knowledge

A little thought experiment: A person is swimming in a calm lake and the sky is dark. Suddenly a huge heavy raindrop falls like a minivan. He hits the water next to the buoy, then another, and more.

This is what thin-legged waterfowl must feel when it rains naturally. The only difference is that the insects, which range in size from one to two centimetres, do not swim, but walk briskly through the water. All this while surviving the impact of raindrops 40 times heavier.

Researchers led by engineer Andrew Dickerson from the University of Tennessee in Knoxville, USA, have discovered exactly how waterfowl survive such heavy rainfall. Like them in the trade magazine Proceedings of the National Academy of Sciences (With people) reports that waterfowl survive even when pushed underwater by a raindrop.

In some cases, the insects were able to remain under water for more than ten minutes

Waterfowl are amazing creatures. They are found all over the world, in ponds, lakes and rivers. It is especially popular in humid and rainy areas. Some species even spend their entire lives in the sea. In order to be able to walk on water, insects distribute their low body weight, which does not exceed a few milligrams, over a large area using their long, thin legs. The legs are covered with microscopic hairs that trap air and help insects get pregnant by the surface tension of water.

For their experiment, Dickerson and his colleagues placed some waterfowl in an aquarium and sprayed the animals with particularly thick drops. The researchers recorded the experience with high-speed cameras. You can see in the videos how water drops create craters on the surface of the water. Some water barriers are thrown away by force, while others are pulled under the water by the suction of a diving drop or sink as a result of a direct hit.

Dickerson and his team are now able to observe how a thin layer of air protects the insects' bodies. Small bristles prevent water from penetrating and prevent animals from getting wet. The atmosphere also gives water buoyancy. Once submerged, they fight their way back to the surface with some vigorous swimming movements of their legs.

In some cases, the insects were able to remain underwater for more than ten minutes, according to the researchers. However, their chances worsened over time. Because the hairy cortex gradually becomes saturated with water. As a result, the insects no longer have enough buoyancy to reach the surface.