[Applause] everyone loves dolphins the way they glide through the water and jump through the air is truly magical [Music] dolphins are not only adorable but they also have the unique ability to navigate and hunt in the darkness of the ocean depths where little light penetrates how do they achieve this impressive feat they do so using a sense called echolocation this is a unique ability to see the world through sound and it is an ability that dolphins share with porpoises bats and whales echolocation functions much like sonar on a submarine so why would they need echolocation if you have ever looked underwater in the ocean you know the view is often murky and not very clear this gets significantly worse the deeper under the sea you go where there is little light [Music] in such conditions how does echolocation work exactly it works by allowing dolphins to see by interpreting the echos of sound waves that bounce off nearby objects dolphins emit ultrasonic clicks by pushing air between the nasal passages when these passages open and close the surrounding tissues vibrate and produce sound waves an organ called the melon located on the Dolphins head concentrates and amplifies these sound pulses and sends them forward these sound waves travel through the melon and into the water bouncing off nearby objects the clicks or sound waves then return to the dolphin as echoes the echoes are picked up by the Dolphins lower jaw and forehead which worked like antennas to receive the signals from there the signals are channeled through the ears and back into the brain the brain can then interpret them allowing the dolphin to see by using sound this process is so precise that dolphins are able to determine the shape size speed and direction of the objects around them it can even determine the internal structure of some objects at this point you may be wondering how humans look to dolphins underwater as our bodies consist mainly of water we provide a prime target for echolocation if a dolphin were to use echolocation on us they would be able to see muscle bone and scar tissue and even artificial body parts this would be enough information for them to tell one human from another so who discovered echolocation one of the first people to study dolphin echolocation in depth was scientists jacques-yves cousteau he wrote a book about the process called the silent world which was published in 1953 how echolocation came to be is believed to be a matter of evolution it is probable that echolocation evolved in order to allow dolphins to survive in the seas harsh environments dolphins require echolocation to navigate hunt and protect themselves from predators how about sound frequency interestingly enough dolphins produce low-frequency signals to communicate but high-frequency signals when echolocating dolphins can produce sounds with a frequency of up to 130 kilohertz this is really impressive since even animals such as dogs and cats which are known for their amazing hearing capabilities cannot hear at such frequencies however this does make dolphin sensitive to the level of noise around them excessive noise such as that given off by boat engines can disorient them and even cause them to lose their hearing over time so let's keep our C's nice and quiet for the sake of our animal friends [Music]