[00:03] hundreds of kilometers from their roost and navigate home autonomously. Humans selectively bred them to supercharge this natural homing ability until they functioned as a wireless communication
[00:15] network. They announced the winner of the Olympic Games and carried life-saving messages in war zones. But how do they do it? [music] Pigeons build up a map of their environment from sights and especially smells. They begin
[00:27] to learn wind-borne odors around their lofts as checks, so even if they're blown off course, they can still sniff their way home. Cross-checking the sun's position with their internal clock gives them an onboard compass. But that's not
[00:39] their only trick. As a pigeon travels through Earth's magnetic field, the motion induces electric currents in fluid-filled loops in their inner ears. Proteins sensitive enough to detect the signals can give them coordinates and
[00:51] directional cues similar to how sharks sense their prey. Though we slowly replaced pigeons with wires, they didn't disappear. The birds cleaning up crumbs in cities today are descendants of a living network whose story is
[01:04] living network whose story is inseparable from our own.