As they report this week in Scientific Reports, researchers from the University of Copenhagen analyzed DNA extracted from the teeth of the unusual whale, which had been caught by a subsistence hunter in 1990 in Disko Bay, West Greenland. Based on the appearance of the skull and its teeth, scientists had suspected that it came from either a beluga-narwhal hybrid or an anomalous beluga.
In particular, the researchers led by Copenhagen's Eline Lorenzen compared genome-wide data generated from that sample to a reference panel of narwhal and beluga DNA to find that the skull came from an F1 hybrid of the two. Mitochondrial analysis further indicated that the mother was a narwhal.
This, the researchers note, raises questions about the mating practices of narwhals and belugas.
The University of Washington's Kristin Laidre, who was not involved in the study, tells Science News that she doesn't think that such hybrids are common, otherwise more would have been discovered. "But I wouldn't be surprised if there were other hybrids," she adds.