You (and by ‘you’ I mean humans) can hold your nose closed indefinitely and survive because you can still breath through your mouth. A human nose could be closed completely (by a deviated septum for example) and said human would still survive as long as they separated eating from breathing, although it would probably lead to hyperventilation, high blood pressure and heart problems. However, if you’re a dolphin who breathes solely through a blowhole, holding your blowhole closed or suffering an injury that close it permanently would lead to a quick death by suffocation.
Except for one strange and lucky dolphin in New Zealand who is the first known dolphin to learn to live by mouth breathing.
Stephen Dawson, a researcher at the University of Otago in Dunedin, New Zealand, was studying Hector’s dolphins (Cephalorhynchus hectori) in 2014 as part on an effort to save the endangered species. He and colleagues noticed one with unusual behavior – it rose high out of the water at an angle, kept its blowhole shut, opened its mouth wide and sounded as if it were sucking in air. This is physically impossible for a dolphin to do due to the plug in its larynx – the goosebeak or epiglottic spout – that causes a complete separation of its respiratory system and digestive tract. In other words, mouth breathing is impossible for dolphins.
And yet … Dawson saw this dolphin seemingly doing just that. Whatever it was doing, it worked because the same dolphin – identifiable by a small tattoo-like lesion near its blowhole, was seen frequently and even recorded on video in December 2015. That footage has been analyzed and, in his new article in Marine Mammal Science, he speculates that the dolphin was either injured or had a muscular defect in its blowhole.
Video and photographs of 38 surfacing sequences show that this individual dolphin did not breathe normally, via its blowhole, but appeared to be breathing mostly via its mouth. We think this dolphin has found a workaround to what is most likely a pathological problem.
Does this mean dolphins are evolving into mouth breathers? Probably not. However, it does cast doubt on the belief that it’s impossible, It may be that all dolphins can do it – they just don’t have a need or desire to. Whatever the case, Dawson says it hasn’t caused a probellm for this one.
[It’s] in great condition and looks absolutely normal, except for this weird breathing behavior.
Think about that the next time you call someone a “mouth breather.”