The animal was one of three whales killed during subsistence hunting off the shore of Greenland in the mid 1980s, Science News reported.
The analysis, published Thursday in the academic journal Scientific Reports, found the male whale had a narwhal mother and a beluga father.
The three whales all had pectoral fins shaped like belugas and tails shaped like narwhals. Only one of the whales remains have been preserved.
The skull was given to researchers by an Inuit hunter who said he had never seen anything like it.
DNA analysis in the 1980s was primitive, so scientists used analytical techniques usually applied to ancient DNA and found the whale was half beluga, half narwhal.
It’s unclear if the hybrid whale is an anomaly, a marine biologist from the University of Washington said, because scientists "infrequently" study remote Arctic whales.
Scientists don't know if the hybrid mammal could reproduce, Science News reported.