1. Next

2. “ One of the most remarkable discoveries Of the modern times has been long-range Scanning devices like radar and sonar.” “ But these electronic marvels of radar and sonar are matched and even surpassed by the echo ranging of such animals as the bat and the bottlenose dolphin or porpoise.” Bats, though not completely blind are said to not have very good vision. The expression blind as a bat refers to someone who doesn’t see very well without their glasses. “ Bats catch night flying insects on the wing by listening to the echoes of their own rapidly beating cries.” “ A blind man tapping with a cane-and hence producing a regular sequence of sound pulses is probably the closest human analog to the remarkable sonar systems of the porpoise or the bat.” Table Of Contents Next Previous

17. Previous Next Table of Contents