Shark embryos can detect potential predators

BBC : Scientists at the University of Western Australia have published new findings on the survival instincts of shark embryos. Ryan Kempster and colleagues studied brownbanded bamboo sharks, whose embryos develop in leathery egg cases separate from their mothers. As the embryo grows, the egg case starts to open, leaving the embryo exposed to predators. To find out what the embryos might do in the presence of such external threats, the researchers placed them in a water-filled tank and generated electric fields that mimicked those emitted by potential predators. The shark embryos responded by stopping their gill movements and staying still. The researchers were not surprised that the embryos responded, but they hadn’t anticipated that the embryos could become conditioned to the stimuli. Kempster believes the research may benefit both sharks and humans by leading to the development of more effective shark repellents.