One of the study's authors, Robin Baird, a marine biologist with Cascadia Research Collective, based in Washington state, said his team was able to get a biopsy sample.

After looking into the animal’s genetics, they confirmed it was a hybrid, which they named Steno bredanensis., The Garden Island website reported.

Baird cautioned against calling the animal a "wholphin".

"I think [that] just confuses the situation more than it already is," he said.

The label "wholphin" has stuck for a hybrid of a false killer whale and an Atlantic bottle-nose dolphin born at Hawaii's Sea Life Park in 1985. The hybrid named Kekaimalu still lives at the marine mammal park, where she helps teach children about genetics.

News of the hybrid seen in the wild during US Navy-funded research to study the effects of sonar, proves the "genetic diversity of the ocean", Sea Life Park curator Jeff Pawloski said.

"I always thought they were out there in the wild existing - it only makes sense," he said. "And to know she has cousins out there in the ocean is an amazing thing to know."

While some news organisation have described the melon-headed whale and rough-toothed dolphin hybrid as a new species,  other things need to occur in order for that to happen, including more widespread hybridisation, Baird said.

"That isn't the case, although there are examples where hybridisation has resulted in a new species," he said. "There's no evidence to suggest it's leading toward anything like species formation."

The male hybrid presents an opportunity to look for others. Hybrids generally occur when there's a decline in the population in one of the parental species, so scientists will be looking out for such a decline.

A likely scenario for how the hybrid came to be is a melon-headed whale getting separated from its group and ending up travelling with rough-toothed dolphins.

Scientists aren't sure how old it is, but believe it's close to being an adult.

AP, Fairfax Media