Since 2016, scientists have been tracking a pod of beluga whales that seems to have adopted a lone male narwhal in Canada's St. Lawrence River. At about 12 years old, the narwhal is reaching sexual maturity, and experts are watching to see if the lone male will mate with one of its beluga peers to produce a hybrid known as a "narluga," reports Robyn White for Newsweek.
The narwhal was first spotted after scientists at the Group for Research and Education on Marine Mammals (GREMM) used a drone to study social behaviors in beluga whales. Since joining the beluga pod, the narwhal has made itself at home and appears to be fitting in.
"It behaves like it was one of the boys," says Robert Michaud, GREMM's president and scientific director, to CBC's Emily Chung in 2018. "It's like a big social ball of young juveniles that are playing some social, sexual games."
Belugas and narwhals belong to the same cetacean family, Monodontidae, and bob around in the Arctic Ocean. However, belugas will migrate farther south in the winter when sea ice forms, while narwhals stay in the Arctic and spend up to five months under ice-covered waters, per Newsweek.
The two species rarely interact in the wild, so it is surprising to researchers how the narwhal joined the pod. Behavioral ecologist Erica Siracusa tells Newsweek that the narwhal may have joined for protection against predators or because the two species are social creatures. Climate change may also create more interaction between the two species, as it continues to alter northern habitats, reported Brigit Katz for Smithsonian in 2018.
Speculations of narluga hybrids have persisted over time, but it wasn't until 2019 when DNA analysis of a skull confirmed their elusive existence, reports Matt Galloway for CBC. An Inuit subsistence hunter saved the skull of an odd cetacean he had hunted in Greenland in 1980s. It differed from the skulls of both belugas and narwhals, with mini tusks on its upper jaw and corkscrew-like lower teeth. DNA and chemical analysis found that the skull belonged to a first-generation narluga hybrid, according to the study published in Scientific Reports.
However, it is unknown if this narluga ever reproduced. While most hybrid species survive into adulthood, some hybrid species like mules are infertile and others, like the liger—a mix between a lion and a tiger—are fertile.
"We know that hybridization is possible … it did happen a few times," Michaud told CBC.
Researchers suspect breeding is a possibility because of how bonded the narwhal is to the pod of belugas. Lots of interactions between the narwhal and the beluga whales have been seen, including social sexual behaviors in both species, Newsweek reports. For a narwhal to successfully reproduce, it will need to get close enough to the other beluga males to form an alliance. After the coalition is formed, as a group, they will approach and court the female whales, per CBC. Female beluga whales travel in a separate pod to raise and care for the young. If the lone narwhal successfully woos a female beluga, researchers will have to wait for it to grow to distinguish it from beluga calves.
Until then, scientists are gearing up to observe the unique pod of mammals when they return to the St. Lawrence River as early as late March to study their communication. It is currently not known if the narwhal can understand beluga vocalizations, per CBC.
"It's fun, it's intriguing, but it's also very powerful and useful information for us tracking the life of this narwhal amongst the belugas," Michaud tells CBC. "If he's doing well, he might be here for the next 40 years — they live up to 60, 80 years old."