Embryonic Sharks Can Sense Predators' Electric Fields: Study

Embryonic sharks can sense electric fields generated by predators and lay still in their egg cases without any movements, reveals a new study.

Adult sharks use sensitive receptors known as the ampullae of Lorenzini to detect electric fields generated when a potential prey contracts its muscle.

But this new study by researcher Ryan Kempster, a marine neuroecologist at the University of Western Australia, has found that some species of baby sharks still developing in egg cases can also sense danger by detecting the electric fields emitted by the predator.

For the study, Kempster and his team examined the brown-banded bamboo shark (Chiloscyllium punctatum) in the lab.

Bamboo sharks do not give birth to live young ones. Instead, they lay eggs in which embryos develop. It will take at least five months for the eggs to hatch. Until then, the embryos have to spend their time inside the egg cases, during which they become vulnerable to attacks from predators like fish and large mollusks, reports LiveScience.

When the research team introduced electric fields mimicking the signals generated by predators, they found that the embryonic sharks sensed the signals and reduced their respiratory gill movements to escape from predator attacks.

Kempster believes that the study might help in developing shark repellents to protect ocean users from shark attack, as well as protect the sharks from getting killed.

"Despite being confined to a very small space within an egg case where they are vulnerable to predators, embryonic sharks are able to recognize dangerous stimuli and react with an innate avoidance response," Kempster said in a statement. "This knowledge may help us to develop effective shark repellents."

The findings of the study, "Survival of the Stillest: Predator Avoidance in Shark Embryos", are published in the journal PLOS ONE.

Check below the video showing how the embryonic bamboo sharks avoid predator detection. This video was posted by Ryan Kempster from The University of Western Australia.