Baby brown-banded bamboo sharks (Chiloscyllium punctatum) still developing within leathery egg cases can sense the electric fields of predators and freeze in place to avoid detection, researchers report online Jan. 9, 2013, in the journal PLoS ONE.
The brown-banded bamboo shark is commonly found on inshore coral reefs and over sandy and muddy bottom habitats ranging in depth from 0-279 feet (0-85 m), according to the Florida Museum of Natural History.
Scientists had known that like other sharks, adult bamboo sharks are equipped with a network of sensors on their heads called ampullae of lorenzini that can detect minute electric fields emitted by both predators and prey.
The rectangular egg capsules were once whimsically called mermaid's purses or devil's purses. These egg cases often possess long tendrils at each corner that help anchor them to surfaces. Even inside the case, however, the developing babies are vulnerable to attack from fish, marine mammals and even large mollusks.
Here, a baby brown-banded bamboo shark wriggles out of its egg case.
Learning more about such shark behaviors may help researchers develop effective shark repellents, ones that generate electric fields that sharks keep away from, said researcher Ryan Kempster, a marine neuroecologist at the University of Western Australia.
Here, a juvenile brown-banded bamboo shark.
Adult males reach sexual maturity at 27-30 inches (68-76 cm) in length, while females mature at 25 inches (63 cm) in length.