Bizarre snake uses two head tentacles to sense and hunt prey

February 3rd, 2010 - 1:35 pm ICT by ANI  

Washington, February 3 (ANI): A new study has revealed that the bizarre tentacled snake uses its two head tentacles to “see” and pursue prey in murky lakes and slow-moving rivers in Southeast Asia.According to a report in National Geographic News, Ken Catania, a biologist at Vanderbilt University in Tennessee, and colleagues observed that the tentacled snake hunts in a strange way. It forms a J with its body, slightly moving its lower midsection when fish swim by. This movement usually causes a fish to dart in the opposite direction, straight toward the snake’s mouth.Even after figuring out the snake’s technique, the scientists were left wondering what the tentacles were for.”We suspected they were fish detectors, as the snake is unusual in specializing almost completely on fish as prey,” said Catania.To solve the mystery, Catania and colleagues first marked tentacle nerve fibers of dead snakes with fluorescent dye and viewed them under a microscope. The team found that many nerves crossed the centers of the tentacles rather than at their surfaces. That finding was intriguing: Nerve cells associated with senses such as taste and touch are not usually so deeply embedded. The structure suggested that these nerve cells were positioned to sense movement of the entire tentacle rather than detailed surface sensations, according to the study.In another experiment using live snakes, the team stroked the appendages with tiny hairs while simultaneously monitoring electrical activity in the snakes’ brains.They also found that the tentacles sensed even the smallest movements of water generated by a nearby vibrating sphere, suggesting the tentacles would also respond to similar movements made by nearby fish.Following the nerve signals, the team noticed that touch signals from the tentacles ran to a part of the brain that registers vision, meaning that the two senses-touch and vision-work closely together in the tentacles.As a final test, Catania put fish in the tank with the snakes, turned off the lights in the laboratory, and monitored the snakes-which have perfectly good eyesight-with infrared cameras. The predators caught fish in total darkness with no trouble. (ANI)

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