The great white shark has the most fearsome reputation of all sharks. But it might not be the biggest of the predator sharks. That honor might go to the Pacific sleeper shark. The biggest one ever seen appeared to be about 23 feet long—longer than the biggest great white.
The Pacific sleeper is found mainly in cold waters around the rim of the northern Pacific Ocean. But some have been seen in warmer waters close to the equator.
Have you ever heard of “mosquito ringtones”? They’re phone ringtones that teens can easily hear but the frequency is too high for adults to hear, since humans naturally start losing the ability to hear higher frequencies in their 20s. New research suggests that some whale species use a similar trick—for very different reasons. Instead of trying to hide the sound of a ringing phone from adults, some whales call at frequencies too low for predators to hear.
