Page 88 - Design in Nature

SONAR INSIDE A DOLPHIN'S SKULL

A dolphin can distinguish between two different metal coins under
water in complete darkness and up to 2 miles (3 kilometres) away. Does it
see that far? No, it does this without seeing. It can make such accurate
determinations by means of the perfect design of an echolocation system
inside its skull. It gathers very detailed information on shape, size, speed
and structure of near objects.
It takes some time for a dolphin to master the skills needed to use such
a complicated system. While an experienced adult dolphin can detect most
objects through a few signals, a juvenile has to experiment for years.
Dolphins do not use their echolocation just to detect their
surroundings. Sometimes they group during feeding and emit high-pitched
sounds so powerful that they dazzle their prey, which are then ready to be
picked up. An adult dolphin produces sounds inaudible to humans (20,000
Hz. and above). The focusing of soundwaves is done in several areas of the