A narluga is a hybrid born as a result of inter-species nookie between a narwhal and a beluga whale. This unusual mash-up of species has never been documented alive, but scientists know they exist thanks to a skull found by Inuits in the Arctic and DNA evidence.
Despite their similarities, you’re unlikely to mix up the two species. Beluga whales are a striking white color and have bulbous foreheads, known as a melon, while narwhals are mottled grey and feature an extremely long unicorn-like "tusk,” which is technically a really big tooth.
Belugas live in the Arctic seas and nearby sub-Artic waters in the northern parts of the Atlantic and the Pacific, while narwhals are restricted to just the Atlantic Arctic. However, their geographical ranges do overlap during winter migrations in the Baffin Bay area around Canada and West Greenland.
Within this territorial overlap, the two species do run into each other and have been known to interact. In an exceptional incident, researchers came across a pod of beluga whales that had taken in a lost juvenile narwhal.
Inuit hunters have spoken to researchers about unusual whales they’ve caught that appeared to be half-beluga and half-whale, generating a fair amount of speculation that hybridization between the species might occur in the wild.
However, the existence of narlugas had not been confirmed by science until 2019. Scientists at the Natural History Museum of Denmark carried out a genetic analysis of a skull that many believed to have belonged to a beluga-narwhal hybrid.
Confirming their suspicions, the DNA test 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 and their father was a beluga.
The researchers 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 hunters who caught the whale vividly recalled its appearance, telling the scientists the individual was gray all over with the tail of a narwhal and the flippers of a beluga whale.
The mating strategies of belugas and narwhals are not widely understood. Breeding typically occurs in the springtime when the whales are particularly difficult to observe due to the broken-up sea ice. Narwhals are also very shy and skittish around humans, making them very difficult to study.
Given this gap in knowledge, it’s unclear how any interbreeding between the two species would occur, physically speaking. The two species also tend to breed in the spring, yet their natural ranges only overlap during the winter months, which raises questions about when the mating occurred.
Species hybridization among cetaceans is rare, but not unheard of. Nicknamed wolphins, a handful of hybrids have been born as a result of mating between bottlenose dolphins and false killer whales.