Researchers say a bamboo shark embryo will cease gill movements in response to an electrical stimulus. The sharks use highly sensitive electroreceptors to detect the electric fields emitted by potential prey. It appears some sharks can also use these electroreceptors to detect predators. The shark embryo reacts to the electrical stimulus by immediately ceasing gill movements - an innate avoidance response.
Nina Sen is a frequent contributor to Live Science’s Life’s Little Mysteries series: an exploration and explanation of our world’s phenomena, both natural and man-made. She also writes astronomy photo stories for Live Science's sister site Space.com.