Don’t tell New Yorkers, but snakes are once again in the news. This time, however, it’s not rampaging rat snakes we must worry about, but a southeast Asian water snake with the fish-catching ability of a tournament pro.
It’s called, appropriately enough, the tentacled snake, and a Vanderbilt University researcher recently documented how this snake uses its body to – in essence – make fish swim right into its mouth.
“I haven’t been able to find reports of any other predators that exhibit a similar ability to influence and predict the future behavior of their prey,” says Kenneth Catania, associate professor of biological sciences at Vanderbilt University, who has used high-speed video to deconstruct the snake’s unusual hunting technique…. “The snake forms an unusual “J” shape with its head at the bottom of the “J” when it is fishing. Then it remains completely motionless until a fish swims into the area near the hook of the “J.” That is when the snake strikes.
The snakes’ motions take only a few hundredths of a second and are too fast for the human eye to follow. However, its prey reacts even faster, in a few thousandths of a second. In fact, fish are famous for the rapidity of their escape response and it has been extensively studied. These studies have found that many fish have a special circuit in their brains that initiates the escape, which biologists call the “C-start.” Fish ears sense the sound pressure on each side of their body. When the ear on one side detects a disturbance, it sends a message to the fishes’ muscles causing its body to bend into a C-shape facing in the opposite direction so it can begin swimming away from danger as quickly as possible.
_Catania is the first scientist to study this particular predator-prey interaction with the aid of a high-speed video camera. When he began examining the movements of the snake and its prey in slow motion, he saw something peculiar. When the fish that the snake targets turn to flee, most of them turn toward the snake’s head and many literally swim into its jaws! In 120 trials with four different snakes, in fact, he discovered that an amazing 78 percent of the fish turned toward the snake’s head instead of turning away.”Once the C-start begins, the fish can’t turn back,” Catania says. “The snake has found a way to use the fish’s escape reflex to its advantage.”
The specialized body fake the snake uses is obvious in the slow-motion video. A little wiggle, the fish’s C-start is triggered and it turns right into the snake’s waiting mouth. How cool is that?