Silence of the deep

ICHTHYOSAURS, the swift marine predators that swam the seas of the early
Cretaceous period, may have been stone deaf. Skeletons of the dolphin-like
reptiles are common, but little had been known about the internal structure of
their skulls until Ben Kear, a palaeontologist at the South Australian Museum in
Adelaide, ran one through a hospital CAT scanner. The X-rays revealed that the
skull’s tiny inner ear bones were too thick to detect sound vibrations. But Kear
says the scan also indicates that, like modern sharks, the 110-million-year old
beast may have been able to detect electrical signals.