The hybrid was likely fathered by a rough-toothed dolphin while it's mother is believed to be a melon-headed whale. Researchers believe a melon-headed whale was the mother of the hybrid. 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. With the head and body of a melon-headed whale and the steep dorsal fin of a rough-toothed dolphin, their interest was piqued.
They tagged a pair of the melon-headed whales that live in the region to see where they traveled, only to realize one didn't look quite like it should.
"Hybrids among different species of whales and dolphins have been previously recorded, but this is the first case of a hybrid between these two species, and only the third confirmed case (with genetics) of a wild-born hybrid between two species in the family Delphinidae", or oceanic dolphins, Baird said. This provided additional information on the effects which Navy sonar has on local marine life.
In a report published this month, the researchers said it had "pigmentation and morphological characteristics suggesting it may be a hybrid".
The team was able to obtain a biopsy, using a crossbow equipped with a special dart that prevents deep penetration and returns a skin sample.
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. Robin Baird, a marine biologist who led the expedition, called it a "most unusual finding", and the first known hybrid between the species.
"To know she has cousins out there in the ocean is an incredible thing to know".
Some hybrid animals, such as the mule - a hybrid of a male donkey and female horse - are mostly sterile and therefore can not propagate easily.
Hybrids generally occur when there is a decline in the population in one of the parental species, so scientists will be looking out for such a decline.
Melon-headed whales, he explains, usually travel together in groups of around 250.
The male "wholphin", which is believed to be close to adult age, was spotted swimming with dolphins near the island of Kauai a year ago, according to Dr Robin Baird, the marine biologist who headed the expedition.
This latest hybrid animal is not the first to be branded with the "wholfin" name.
Killer whales (Orcas) are also Delphinidae or dolphins.
"To know she has cousins out there in the ocean is an unbelievable thing to know", said Sea Life park curator Jeff Pawloski in response to the new discovery, which he said was proof of the "genetic diversity of the ocean".