Baby sharks still developing in their egg cases can sense when
predators2 are near, and keep very still to avoid being detected, according to research published January 9 in the open access journal PLOS ONE by Ryan Kempster from the University of Western Australia and colleagues. Adult sharks are known to use highly sensitive receptors to detect electric fields emitted by potential
prey3. In the current study, researchers found that
embryos4 of some shark species employ similar means to detect potential predators and escape being eaten.
The researchers found that, even within their egg cases, brown-banded bamboo shark embryos can sense electric fields that
mimic5 a
predator1, and respond by reducing
respiratory(呼吸的) gill(腮) movements to avoid detection. According to the authors, their results suggest that even at these early stages,
embryonic6 sharks can recognize dangers and
instinctively7 try to avoid them.
Kempster adds, "Despite being confined to a very small space within an egg case where they are vulnerable to predators, embryonic sharks are able to recognise dangerous
stimuli8 and react with an
innate9 avoidance response. Knowledge of such behaviours may help us to develop effective shark
repellents(排斥的,防水的)."