A narluga (

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

narwhal The narwhal (''Monodon monoceros'') is a species of toothed whale native to the Arctic. It is the only member of the genus ''Monodon'' and one of two living representatives of the family Monodontidae. The narwhal is a stocky cetacean with a ...

and

beluga Beluga may refer to: Animals *Beluga (sturgeon) * Beluga whale Vehicles * Airbus Beluga, a large transport airplane * Airbus BelugaXL, a larger transport airplane * Beluga-class submarine, a class of Russian SSA diesel-electric submarine * U ...

) is a

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

born from mating a female narwhal and a male beluga whale. Narwhals and beluga whales are both

cetaceans Cetacea (; , ) is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively c ...

found in the High

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

and are the only two living members of the family

Monodontidae The cetacean family Monodontidae comprises two living whale species, the narwhal and the beluga whale and at least four extinct species, known from the fossil record. Beluga and narwhal are native to coastal regions and pack ice around the Arcti ...

Discovery

The existence of narlugas had been hypothesized for decades before its discovery. There are 20 known cetacean hybrids in existence, with 7 of those occurring only in captivity. In 1990, the researcher Mads Peter Heide-Jørgensen spoke to an

Inuk Inuit (singular: Inuk) are a group of culturally and historically similar Indigenous peoples of the Americas, Indigenous peoples traditionally inhabiting the Arctic and Subarctic regions of North America and Russia, including Greenland, Labr ...

hunter who'd captured an unusual hybrid animal that had both beluga and narwhal anatomy. He noted seeing two other anomalous individuals, but no part of them was retained. When Heide-Jørgensen was shown that skull, he determined that it belonged to an unknown Monodontidae. Through analysis of anatomical characters, he and a colleague found that the specimen had some descriptive properties which fell between a narwhal and a beluga. In particular, the characteristic narwhal 'horn' is anatomically a tooth; the unidentified specimen lacked a single narwhal tusk, but its teeth were spiraled, like the tusk of a narwhal. The specimen had 18 teeth, an intermediate number when compared to the beluga (40 teeth) and the narwhal (one tooth). However, not all characters fell between those of narwhals and belugas; the potential hybrid had a skull larger than is usual for either species. The hybrid genetics of the narluga was confirmed in 2019 when the

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

of the specimen was sequenced.

Carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

isotopic analysis also found that narlugas have a greater C/N concentration than both parent species.

Feeding

Narwhals and beluga whales are both

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

feeders, with the largest portion of their diet consisting of

Arctic cod ''Arctogadus glacialis'', known also with ambiguous common names Arctic cod and polar cod, is an Arctic species of fish in the cod Family (biology), family Gadidae, related to the true Gadus, cod (genus ''Gadus''). ''Arctogadus glacialis'' is fo ...

. Through analysis of stable isotopes, Skovrind et al. determined that the hybrid had isotopic carbon readings consistent with that of a benthic foraging strategy. The hybrid had outward-facing teeth in its bottom jaw which may have aided in this benthic foraging strategy, allowing it to capture prey more effectively, scooping it off the ocean floor. This proposed foraging strategy differs from that of the gray whale, which rolls on its side on the ocean floor to consume benthic prey. This may fill the niche left open by the anthropogenically extinct Atlantic gray whale, a relative of the benthically feeding Pacific gray whale.

Species compatibility

Despite being each other's closest living relative phylogenetically, narwhals and beluga whales diverged an estimated four million years ago; however, it is predicted that gene flow continued until 1.25–1.65 million years ago. Narwhals and beluga whales have overlapping ranges in the northern Atlantic and Pacific Oceans. As a result of climate change, Arctic cetaceans are at high risk for range contraction, which is likely to increase interspecific interaction between narwhals and belugas whales. Both species exhibit seasonal migrations, and they are most likely to overlap with one another in their summering grounds. Beluga whales and narwhals use high frequency vocalizations for echolocation; while beluga whales typically utilize higher frequency vocalizations than do narwhals, their vocalization ranges are overlapping. Both species show evidence of context-dependent vocalizations. This indicates possible social compatibility between the two species. However, narwhals also show evidence of pod-specific vocalizations, potentially serving as a barrier to hybridization with beluga whales. The two parental species share a spring

mating season Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and ch ...

, but their

mating system A mating system is a way in which a group is structured in relation to sexual behaviour. The precise meaning depends upon the context. With respect to animals, the term describes which males and females mating, mate under which circumstances. Reco ...

s differ. Beluga whales are thought to be more monogamous, whereas narwhals operate under a more polygamous mating system, further differentiating the two socially. Current data on narwhals, beluga whales, and their hybrids is not sufficient to state definitively, but the prevailing thought is that the hybrid would likely not be reproductively viable. In spite of their potential for social incompatibility, the last recorded sighting of the two species comingling was in 2018, when a narwhal was captured via drone footage schooling with a pod of beluga whales.

References

External links

{{Mammal hybrids Mammal hybrids Intergeneric hybrids