Researchers have turned a discovery into a whale – a hybrid of a beluga whale and a narwhal.
A DNA analysis of the whale's skull confirmed that it was the male offspring of a narwhal mother and a Beluga father 20 in Scientific Reports .
The animal was one of three unusual whales caught in 1986 or 1987 during a subsistence hunt in Disko Bay in West Greenland. The three whales were all uniformly gray and had pelvic fins in the form of belugas and tails in the form of narwhals.
The Inuit hunter, who gave the researchers the skull, said he had never seen such strange whales before or since. says Eline Lorenzen, evolutionary biologist and curator of the Danish National Museum at the University of Copenhagen, where the skull is housed. Disko Bay is one of the few places where belugas and narwhals overlap during the mating season.
Earlier DNA analyzes of the decades-old skull were "lousy," says Lorenzen. Therefore, they and colleagues used techniques to analyze the old DNA to establish that the animal has a mixture of beluga and narwhal DNA of about 50 to 50, making it a first generation hybrid ( SN: 1
Prior to the new study, there was the clearest indication that the animal was neither pure beluga nor full-necked whale Randall Reeves, a whale biologist, chairman of the International Union for the Conservation of Nature in the group of whale specialists, says his teeth are distinguished from those of both Arctic species. Reeves helped decades ago to call the skull a potential hybrid, but was not involved in the new research.
Beluga whales have 40 spiny teeth. Female narwhals have no teeth, while female narwhals have one, sometimes two spiral teeth, which drill through the lip and form the famous "tusk". The male hybrid had forward grooved teeth, but not the long tusk.
It is not clear whether the tusk sometimes interferes with the narwhal mating, but it is a distinguishing feature that could warn a female beluga that a male narwhal is a different species. Female narwhals, however, are similar in size and shape to female belugas and could be more easily confused with them, says Reeves of Hudson, Canada. "A female narwhal impregnated by a male beluga is quite believable."
However, for some researchers who studied the species for years, the mating is unusual, even shocking, without foreshadowing such mingling. The branches of the beluga and narwhals of the whale's family tree split off about 5 million years ago – at about the same time, the ancestors of humans and chimpanzees went their separate ways. Lorenzen's team has also found no evidence of hybridization in the DNA of other belugas and narwhals in the last 1.5 million years. When the team presented the findings at a Beluga researchers conference in Mystic, Connecticut, in March, "we heard a pin drop when we said it was a first-generation hybrid," says Lorenzen. "They were so surprised."
Given how rare people observe whales in the remote Arctic, it's hard to tell if the hybrid is a coincidence, says Kristin Laidre, a marine mammal biologist and narwhal expert at the University of Washington in Seattle. "I do not think it's a very common thing," or big subsistence hunts would have uncovered other specimens, she says. "But I would not be surprised if there were other hybrids."