It's recently been confirmed that this skull, believed to be a unique specimen, belonged to the first known half-narwhal half-beluga hybrid. Does that make it a "narwhuga" or a "beluwhal?"
Scientists at the Natural History Museum of Denmark have recently carried out genetic analysis of the extremely unusual specimen, officially confirming long-held suspicions that it is the skull of a beluga-narwhal hybrid. Reporting in the journal Scientific Reports, their analysis showed that the male specimen was 54 percent beluga and 46 percent narwhal. Judging by its mitochondrial genome, a small portion of the total DNA that’s only inherited from mother to offspring, the hybrid’s mother was a narwhal.
Scientists first got their hands on the skull in 1990 after spotting it on the roof of an Inuit toolshed in West Greenland’s Disko Bay. The animal was killed some three or four years previously, so the skull was stripped of its flesh, but the hunters remembered the individual clearly: it was gray all-over with the tail of a narwhal and flippers of a beluga whale. Many researchers have since speculated the specimen could have been a hybrid, but they were unable to definitively prove it – until now.
“The skull has been in the museum since, and only now because of methodological developments – and, I guess, my own interest in belugas and narwhals, which my research group are working on – have we been able to revisit the specimen with new methods to confirm its hybrid origin,” study author Eline Lorenzen, associate professor and curator at the Museum, told IFLScience.
"The methods were [previously] not available to confirm whether it was indeed a hybrid – and in which case, was it a first generation hybrid or a backcross or what?"
It's difficult to get any insights into how this hybrid would have behaved or appeared. However, by looking at levels of carbon isotopes in the skull, we do know its diet was different from either parent species, most likely foraging closer to the bottom of the seafloor.
Narwhals and belugas are extremely strange creatures. Together, they make up the only two members of the cetacean family Monodontidae, however, they have some distinct differences. Narwhals are mysterious Arctic-dwelling toothed whales with a single unicorn-like "tusk,” which is technically a tooth. Belugas are an oddly white species of toothed whales with a bulbous “melonhead”, which gives them that nickname.
“Based on genetic data, the species are estimated to have diverged approximately 5.5 million years ago, so they are pretty divergent, although they do share characteristics,” continued Lorenzen.
Both species have small chunks of habitat and some migration routes that cross paths, such as the coast of West Greenland where this specimen was collected. Scientists have also spotted the two species intermingling at the mouth of the St Lawrence River near the Canadian province of Quebec, in what appears to be the case of a gang of beluga whales adopting a lost juvenile narwhal.
However, we know very little about the sex lives of both species as they spend most of their mating season in ice-covered Arctic seas. Evidently, some interspecies Arctic canoodling went on here, however, the researchers still aren’t totally sure how this unlikely phenomenon came about.