Newly Discovered ‘Whale-Dolphin Hybrid’ Is Not A New Species, Scientists Explain

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Earlier this week, several reports suggested that scientists had just discovered a new species off the coast of Kauai, Hawaii; one that was said to be a first-of-its-kind cross between a melon-headed whale and a rough-toothed dolphin. While the researchers behind the discovery clarified over the weekend that the animal is not a new species after all, the so-called “whale-dolphin hybrid” might not be the only peculiar mix of the two aforementioned species out there in the waters.

The discovery was first reported on Thursday by Kauai publication The Garden Island, which wrote that a team of scientists from the Cascadia Research Collective found the species in August 2017 and had just recently confirmed its origins. According to biologist Robin Baird, who led the research group, the “most unusual finding” appeared to be a hybrid due to its combination of features from two different species. The animal was then given the scientific name Steno bredanensis, and documented as the first hybrid of a rough-toothed dolphin and melon-headed whale.

Because The Garden Island and other sources referred to the “whale-dolphin hybrid” as a new species, Baird cleared up the confusion in an email sent to the Huffington Post, explaining that the animal “isn’t, and shouldn’t be” classified as such. The publication cited a previous article from Quanta, which detailed how unusual sightings of a hybrid animal are only rarely considered new species because the hybrids might not be able to reproduce or might get reabsorbed into an existing species when they mate with an animal of the same species as their father or mother.

Although Baird added that it’s possible for hybrids to mate with their own kind and create an actual new species, he noted that he wasn’t able to see any proof of that in the case of the erroneously reported “whale-dolphin hybrid.” He also hinted at the possibility that the sighting from last year isn’t the only one of its kind.

“I wouldn’t be surprised if there are more hybrids between the [melon-headed whale and rough-toothed dolphin] ― they do associate quite regularly,” Baird commented.

“We don’t have any information on population trends for either species in Hawaii, so [we] can’t say whether this is the case, but we’ll be looking for evidence of additional hybrids.”

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In any case, the hybrid spotted by Baird and his colleagues was unique, as pointed out by the Huffington Post, because the animal’s mother, a melon-headed whale, was observed as the only one of her species in a pod of rough-toothed dolphins. Baird noted that this is unusual because melon-headed whales are typically found in large groups, and since the hybrid’s mother had likely been swimming with the rough-toothed dolphin pod “for a while,” he suggested that there’s a strong chance she had mated with other members of the pod.

While Baird did his part to clear up the confusion caused by the earlier reports of a “new species,” the Huffington Post clarified the frequent, potentially misleading use of the term “whale-dolphin hybrid” and explained that the melon-headed whale is actually part of Delphinidae, a family of ocean dolphins that also counts the killer whale among its members.