Sometimes nature is just out to screw with you. There are at least two kinds of shark that can, when handled, bark like dogs. Anyone who wonders if their bark is worse than their bite is welcome to try to find out.
Another day, another way for nature to weird out. Sharks are sleek underwater predators that soundlessly stalk their prey. Except for the sharks that bark like dogs when they feel threatened. At least two kinds of shark, the swellshark and the draughtsboard shark, bark both in the water and on land. So far, scientists don't know exactly how they do it, or whether it's intentional.
Both sharks use the same mechanism to produce the barking sounds. When they are threatened, they suck in water. This makes them appear larger and, if they're in a crevice, can wedge them in place so a predator can't extract them. When they expel the water, they make a hoarse sound that resembles a barking dog. This happens whether the shark is in the water or not, since the shark can make the sound in both water and air. To understand why this is remarkable, try singing with a throat full of water.
The bark may just be a side effect of expelling material, but it may also be an intimidation tactic. Sharks that do this are only a few feet long and make their living eating the small fish and crustaceans in shallow waters along the coast, so they really need help intimidating anything. These are the sharks also regularly caught by people fishing off rocks and peers on the ocean shore, so if you ever reel in a shark, check to see if it barks at you.
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