A dolphin off the coast of New Zealand has been documented doing something unprecedented in dolphin research: breathing primarily through its mouth instead of its blowhole.

The animal is a Hector's dolphin (Cephalorhynchus hectori), an endangered species that was recorded and photographed performing the unusual feat by researchers from the University of Otago.

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Dolphins -- being mammals and not fish -- breathe air. The blowhole on top of their heads functions as the "nose," helping the creatures expel old air and fill their lungs with new air when they surface.

This dolphin, the scientists wrote, consistently surfaced at a sharp angle to the sea, its head bursting higher than normal above the surface of the water. Its blowhole, which should have opened wide, remained shut. Meanwhile, noise consistent with taking in air was "clearly audible as the dolphin opened its mouth."

It was the only dolphin in its group to breathe in that fashion.