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Water snakes trick their fish prey into swimming directly into their waiting jaws, … With a subtle body movement, the tentacled snakes trigger a preprogrammed escape response in fish, causing them to flee in a predictable direction so that the snakes know just where to positions their heads for an easy meal. …
That little twitch is all it takes to initiate the fish's escape response, called the C-start — one of the most well studied neural circuits in vertebrates. Two large nerve cells, known as Mauthner cells, run along either side of the fish's body and detect water disturbances. The cell closest to the signal will fire action potentials that stimulate trunk muscles on the opposite side of the body while simultaneously inhibiting the muscles on the near side. As a result, the fish turns away from the disturbance and flees. This whole process takes less than a tenth of a second.
The tentacled snake takes advantage of this escape response by positioning its neck in a J position, with its head turned back towards its body. … [As] soon as the fish swam into position, the snake simply shook its side to elicit the fish's escape response. Seventy-eight percent of the time, the fish fled away from the snake's body and towards its head instead. …
In order for this type of exploitation to work, the predator must be uncommon — this is known as the "rare predator" effect. Otherwise, the prey would adapt to evade the predator's new hunting strategy. In this case, "most other predators are not using the snake's strategy [of surrounding the fish]. … They're coming from one side to the other."
Similarly, the painted redstart — a small, North American songbird — fans its contrasting tail plumage to evoke the aerial escape response of its insect prey and then "picks them off one by one as they fly up into the air." … People have also been characterized as rare predators. … Worm grunters — people who gather earthworms as bait — generate vibrations in the soil that the worms mistake for their more common mole predators and escape to the surface for easy collecting.