The male "wholphin", which is believed to be close to adult age, was spotted swimming with dolphins near the island of Kauai past year, according to Dr Robin Baird, the marine biologist who headed the expedition.
"And, although rare, other dolphin hybrids are known, such as the offspring of a bottlenose dolphin and false killer whale (also delphinidae), called a wholphin, and the offspring of a beluga whale and a narwhal, called a narluga".
Scientists are touting the first sighting of a hybrid between a melon-headed whale and a rough-toothed dolphin off Hawaii.
However, it wasn't until a biopsy that they were able to confirm their suspicions.
A new species of aquatic mammal, a hybrid of a whale and a dolphin, has been identified in waters near Hawaii.
The first recorded dolphin-whale hybrid was born in captivity at a SeaWorld park in Tokyo in 1981, but died before it reached its first birthday. Like orcas, beluga whales and pilot whales, melon-headed whales are actually a species of dolphin, or delphinidae - and dolphins are a sub-family of whales to boot.
Cascadia has conducted field research in the Canadian Arctic, Alaska, British Columbia, Washington, Oregon, California, Hawai'i, Mexico, and the waters off Central America. But don't call it a "wholphin", they say.
News of the hybrid animal hit headlines across the globe when a paper describing the find was published in July 2018.
Isolated incidents like this aren't generally considered a new species since hybrids often can't reproduce-like the mule, for example, which is a cross between a male donkey and a female horse-it's rare that hybrids are able to create a new species.
'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 unbelievable thing to know".
A likely scenario for how the hybrid came to be a melon-headed whale getting separated from its group and ending up travelling with rough-toothed dolphins. For one thing, hybrids can occur when the paternal species goes through a population drop and "individuals have difficulty finding mates".
Scientists do not know how old the hybrid is, but believe it is close to adult age.
The dolphin-whale hybridization is especially surprising in this region, as a sighting of melon-headed whales had never before been confirmed near the Pacific Missile Range Facility (PMRF) navy base.
This latest hybrid animal is not the first to be branded with the "wholfin" name.
The hybrid named Keikaimalu still lives at the marine mammal park, where she helps teach children about genetics.