June 20 (UPI) -- New DNA analysis suggests a strange whale skull, in museum storage for the last 30 years, belonged to the offspring of a narwhal mother and a beluga father.
The discovery, described this week in the journal Scientific Advances, proves narwhals and belugas can interbreed.
"As far as we know, this is the first and only evidence in the world that these two Arctic whale species can interbreed," Eline Lorenzen, evolutionary biologist and curator at the University of Copenhagen's Natural History Museum of Denmark, said in a news release. "Based on the intermediate shape of the skull and teeth, it was suggested that the specimen might be a narwhal-beluga hybrid, but this could not be confirmed. Now we provide the data that confirm that yes -- it is indeed a hybrid."
In the 1980s, a hunter in Greenland shot and killed a strange-looking whale. He saved the skull. Years later, the skull was examined by scientists, but the specimen defied their classification efforts. Frustrated, researchers put the whale skull in storage at the Natural History Museum of Denmark. Until recently, the skull had been collecting dust.
New DNA analysis techniques have made it possible to identify befuddling animal remains.
The combination of DNA and isotopic analysis confirmed the whale was a first-generation narwhal-beluga hybrid.
The whale's hybridization yielded an unusually large jaw and strange set of teeth. Narwhals have one or two large, spiral tusks. Belugas boast rows of uniform conical teeth. The hybrid whale had a single row of long teeth, both spiraling and pointed, angled horizontally.
"This whale has a bizarre set of teeth," said Mikkel Skovrind, a PhD student at the Natural History Museum. "The isotope analysis allowed us to determine that the animal's diet was entirely different than that of a narwhal or beluga -- and it is possible that its teeth influenced its foraging strategy. Whereas the other two species fed in the water column, the hybrid was a bottom dweller."
Genomic analysis suggests the two species don't have a history of interbreeding. Narwahl-beluga hybrids are either rare, a new phenomena, or both.