Let's go bats

Blind people, without even being aware of the fact, are actually using echoes of their own footsteps and of other sounds, to sense the presence of obstacles

it was only a matter of time before weapons designers adapted it for the detection of submarines

bats, or rather natural selection working on bats, had perfected the system tens of millions of years earlier

Given that there is a living to be made at night, and alternative daytime trades are thoroughly occupied, natural selection has favoured bats.

When  dinosaurs dominated the daytime economy, our mammal ancestors only managed to survive because they found ways of scraping a living at night