S1, E1: We, as humans, have fairly advanced senses, but there is a great deal we can learn from nature. This program looks at how evolution enhances our technology. Great ‘sensers’ include the seal, whose whiskers detect water turbulence after 30 seconds; elephants, who ‘hear’ through their feet over 2 km away; and bats, whose ability to echolocate has led to the design of a bike for blind people.