30 August 2016
Endangered dolphin with broken blowhole learns to mouth-breathe
Steve Dawson, University of Otago
Not just a pretty face? A dolphin has learned to breathe through its mouth after developing a faulty blowhole, highlighting the animal’s ability to adapt.
The adult Hector’s dolphin (Cephalorhynchus hectori) was discovered in January 2014 off the coast of Christchurch in New Zealand.
Steve Dawson at the University of Otago in Dunedin, New Zealand, and his colleagues were studying the endangered species as part of a long-term conservation project, when they noticed unusual behaviour in one member of a group of seven.
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Each time the dolphin surfaced, it approached at a steep angle and lifted its head higher out of the water than normal. The blowhole stayed shut while its mouth opened wide and made a sound consistent with sucking in air.
Dolphins were not thought to be able to breathe through their mouths. To do this, a dolphin would need to move its larynx from the usual position to allow the respiratory and digestive tracts to communicate, says Dawson.
The animal probably learned to do this after its blowhole became blocked by a foreign object or injury, or because the muscles around it didn’t work properly, he says. “We think this dolphin has found a workaround to what is most likely a pathological problem.”
Although habitual mouth-breathing has not previously been documented in these animals, some dolphins in captivity have been recorded using their mouths to blow bubbles during play.
Peter Harrison of Southern Cross University in Australia says the finding fits with previous knowledge about the keen intelligence and adaptability of dolphins. “It wouldn’t surprise me that individuals are making discoveries and thinking ‘well that works, so I’m going to learn from that, and see how I can continue to use it’.”
Dawson’s team has now spotted the dolphin more than half a dozen times and found it to be healthy. “It’s in great condition and looks absolutely normal, except for this weird breathing behaviour,” he says. “Clearly it’s a thing that works for the animal.”
Journal reference: Marine Mammal Science, DOI: 10.1111/mms.12349
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