Whales and dolphins both belong to the same taxonomic order, and are closely enough related that offspring between them can be fertile and have been recorded although they are extremely rare. After encountering a large pod of melon-headed whales, the researchers tagged two of them, to see where they might go.
The animal, which was first spotted off the island of Kauai in August 2017, appears to be the first record of a hybrid involving either species.
The team will be returning to Kauai's waters next month, when they hope to get more photos of the new hybrid whale-dolphin as well as further research on other species in the area. "It isn't and shouldn't be considered a new species", Robin Baird, a biologist with the research group, told HuffPost.
The hybrid was spotted spending most of its time alongside another melon-headed whale by scientists on a two-week tagging and monitoring effort.
"Based on the genetics, the father was a rough-toothed dolphin and the mother a melon-headed whale", he told the outlet. The marine scientists tagged the hybrid with satellite tracking Global Positioning System, along with a companion, to see where they might go.
The melon-headed whale, which the researchers also observed hanging around during their expedition, is also relatively rare in the waters of Hawaii. That's because two animal species are unlikely to have the same number of chromosomes, and hybrids won't be able to reproduce if their parents are too genetically dissimilar. Later they were able to obtain a biopsy sample that proved them correct.
The marine mammal monitoring program, funded by the US Navy, first spotted the animal in August 2017.
It's unknown whether this new animal - which the researchers named Steno bredanensis - could produce viable offspring, but in any case, one hybrid animal does not make a new species.
Scientists who found the specimen tracked numerous species during a study off the island of Kauai a year ago. "I always thought they were out there in the wild existing - it only makes sense", he said.
Four years later, Keikaimalu was born at Hawaii's Sea Life Park in Hawaii, the result of "an unplanned union" between a false killer whale and an Atlantic bottlenose dolphin, according to the Chicago Tribune.
Two of the ocean's most beloved sea creatures morph into one wonderful animal, as a team of researchers discovered in the past year.
Hybrids can be the effect of a population drop in one species and an individual experiences difficulty in finding a mate.
It's unclear if this is true for this latest hybrid animal.