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Video: A fish makes a tongue out of water

On a pane of clear glass, a mudskipper (Periophthalmus barbarus) carefully eyes a piece of shrimp. The predator definitely wants its prey, but actually eating it presents a challenge: Outside of the water, the fish can’t generate enough suction to swallow. However, new research published online today in the Proceedings of the Royal Society B shows that the mudskipper has solved the problem by bringing the water onto land, and that its clever solution may have led to the evolution of true tongues in other land animals. Using a group of high-speed cameras and x-ray videos, the scientists observed the mudskippers feeding in the laboratory. Their analysis showed that the fish were carrying mouthfuls of water up onto the land and then expelling the water at the moment they lunge at their prey. The water allows the fish to form an airtight seal and generate enough suction to move the water and their meal back toward the esophagus. Furthermore, the motion of a bone in the fishes’ throat, known as the hyoid, closely resembles that of other terrestrial animals, especially newts, which use true tongues to eat. The authors suggest that the mudskipper’s “hydrostatic” tongue may serve as the evolutionary bridge that allowed our aquatic ancestors to begin feeding on land.