We all have an anus, but there was a time in our evolutionary past when our distant ancestors did not. In this video, Maddie Moate talks you through the origins and why we have what we have. Subscribe to Earth Unplugged for more amazing animal videos - bit.ly/SubscribeToEarthUnplugged Watch more videos from Earth Unplugged: Animals In Slow Motion And Stunning Time-lapse Photography bit.ly/EarthUnpluggedSlowMotio... Expeditions and Location Films bit.ly/EarthUnpluggedExpeditio... Big Questions With Maddie Moate bit.ly/BigQuestionsWithMaddieM... Wilderness Sessions bit.ly/WildernessSessionsFilms Check out the other two channels in the BBC Earth network: BBC Earth: bit.ly/BBCEarthYouTubeChannel BBC Earth Lab: bit.ly/BBCEarthLabYouTubeChannel About BBC Earth Unplugged: We're Earth Unplugged and we make videos about the incredible natural world and the animals that live here - exclusively for YouTube. We investigate the conundrums, quirks and beautiful science of our amazing planet, delving into the BBC documentary and natural history vaults and mixing it up with our own stuff to take a brand new look at the animals and wildlife of planet Earth. From animal behaviour in slow motion, educational videos, expedition films and beyond we’ve got you covered. Our planet is mind-blowing. Join us as we explore what it has to offer. Subscribe for more: bit.ly/SubscribeToEarthUnplugged You can also also find the BBC Earth community on Facebook, Twitter and Instagram. Want to share your views with the team behind BBC Earth and win prizes? Join our fan panel here: tinyurl.com/YouTube-BBCEarth-... This is a channel from BBC Worldwide who help fund new BBC programmes. This is a channel from BBC Worldwide who help fund new BBC programmes.