Narluga

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Narluga
Narwhal x Beluga.jpg
Specimen at Zoological Museum, Copenhagen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Superfamily: Delphinoidea
Family: Monodontidae
Hybrid: Delphinapterus leucas × Monodon monoceros

A narluga (portmanteau of narwhal and beluga) is a hybrid born from mating a female narwhal and a male beluga whale. [1] Narwhals and beluga whales are both cetaceans found in the High Arctic and are the only two living members of the family Monodontidae. [2]

Contents

Discovery

Skulls of a beluga, narluga, and narwhal Narwhal hybridisation.webp
Skulls of a beluga, narluga, and narwhal

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. [3] In 1990, the researcher Mads Peter Heide-Jørgensen spoke to an Inuk 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. [4] 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. [5] [3] 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. [4]

The hybrid genetics of the narluga was confirmed in 2019 when the genome of the specimen was sequenced. Carbon/nitrogen isotopic analysis also found that narlugas have a greater C/N concentration than both parent species. [1]

Feeding

Narwhals and beluga whales are both pelagic feeders, with the largest portion of their diet consisting of Arctic cod. [6] Through analysis of stable isotopes, Skovrind et al. determined that the hybrid had isotopic carbon readings consistent with that of a benthic foraging strategy. [1] 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. [7] 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. [8] 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. [9] Both species exhibit seasonal migrations, and they are most likely to overlap with one another in their summering grounds. [1]

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. [10] Both species show evidence of context-dependent vocalizations. [11] [12] This indicates possible social compatibility between the two species. However, narwhals also show evidence of pod-specific vocalizations, [12] potentially serving as a barrier to hybridization with beluga whales. The two parental species share a spring mating season, [1] but their mating systems differ. Beluga whales are thought to be more monogamous, whereas narwhals operate under a more polygamous mating system, [13] 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. [8] 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. [14]

Related Research Articles

<span class="mw-page-title-main">Whale</span> Informal group of large marine mammals

Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families: Balaenopteridae, Balaenidae, Cetotheriidae, and Eschrichtiidae. Odontocetes include the Monodontidae, Physeteridae, Kogiidae, and Ziphiidae, as well as the six families of dolphins and porpoises which are not considered whales in the informal sense.

<span class="mw-page-title-main">Narwhal</span> Medium-sized toothed whale species

The narwhal 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 has a similar build to the closely related beluga whale, with which it overlaps in range and can interbreed. The species is characterised by a stocky body with two short, seamlessly upcurled flippers; a shallow ridge in place of a dorsal fin across its back; a prominent melon used for sound propagation; and a large 1.5 to 3.0 m long tusk that is uniquely developed in males. The tusk, which is derived from the left canine, is thought to serve as a weapon or as a tool for feeding, attracting mates or sensing water salinity. Specially adapted slow-twitch muscles, along with jointed neck vertebrae, and the lack of a dorsal fin allow the narwhal to more easily manoeuvre through its Arctic environment, where it spends extended periods at great depths.

<span class="mw-page-title-main">Beluga whale</span> Species of whale

The beluga whale is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus Delphinapterus. It is also known as the white whale, as it is the only cetacean to regularly occur with this colour; the sea canary, due to its high-pitched calls; and the melonhead, though that more commonly refers to the melon-headed whale, which is an oceanic dolphin.

<span class="mw-page-title-main">Monodontidae</span> Family of mammals

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 Arctic Ocean. Both species are relatively small whales, 3–5 m (9.8–16.4 ft) in length, with a forehead melon, and a short or absent snout. Premaxillary teeth are absent. They do not have a true dorsal fin, but do have a narrow ridge running along the back, which is much more pronounced in the narwhal. They are highly vocal animals, communicating with a wide range of sounds. Like other whales, they also use echolocation to navigate. Belugas can be found in the far north of the Atlantic and Pacific Oceans; the distribution of narwhals is restricted to the Arctic and Atlantic Oceans.

In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast, an oligotypic taxon contains more than one but only a very few subordinate taxa.

<span class="mw-page-title-main">False killer whale</span> Species of oceanic dolphin in the genus Pseudorca

The false killer whale is a species of oceanic dolphin that is the only extant representative of the genus Pseudorca. It is found in oceans worldwide but mainly in tropical regions. It was first described in 1846 as a species of porpoise based on a skull, which was revised when the first carcasses were observed in 1861. The name "false killer whale" comes from having a skull similar to the orca, or killer whale.

<i>Lagenorhynchus</i> Genus of mammals

Lagenorhynchus is a genus of oceanic dolphins in the infraorder Cetacea, presently containing six extant species. However, there is consistent molecular evidence that the genus is polyphyletic and several of the species are likely to be moved to other genera. In addition, the extinct species Lagenorhynchus harmatuki is also classified in this genus.

The Cumberland Sound belugas are a distinct population of belugas residing in the Cumberland Sound region of the Labrador Sea off the coast of Nunavut, Canada Individuals of this population reside in the sound year-round, congregating in its extreme north exclusively at Clearwater Fjord during the summer for calving. The Cumberland Sound beluga population is considered fairly isolated and genetically distinct from other beluga populations, with a notable number of haplotypes and microsatellite loci not found elsewhere.

<span class="mw-page-title-main">Muktuk</span> Traditional Inuit and Chukchi food consisting of frozen whale skin and blubber

Muktuk, a traditional food of Inuit and other circumpolar peoples, consisting of whale skin and blubber. A part of Inuit cuisine, it is most often made from the bowhead whale, although the beluga and the narwhal are also used. It is usually consumed raw, but can also be eaten frozen, cooked, or pickled.

East Bay is a waterway in the Kivalliq Region, Nunavut, Canada. It is located in Hudson Bay off eastern Southampton Island. Caribou Island lies to the north of the bay's mouth. The nearest community is Coral Harbour, 35 km (22 mi) to the west.

<span class="mw-page-title-main">NOC (whale)</span> Beluga whale known for making human-like vocalizations

NOC was a beluga whale who made human-like vocalizations. He was captured by Inuit hunters for the United States Navy in 1977 and lived in captivity until his death in 1999. In 1984, researchers from the National Marine Mammal Foundation discovered his unusual ability to mimic the rhythm and tone of human speech. Belugas' human-like voices had been described in the past, but NOC's voice was the first to have been recorded.

<span class="mw-page-title-main">Hans Thewissen</span> Dutch/American paleontologist

Johannes Gerardus Marie (Hans) Thewissen is a Dutch-American paleontologist known for his significant contributions to the field of whale evolution. Thewissen's fieldwork has led to the discovery of key fossils that have shed light on the transition of whales from land to water, including the discovery of Ambulocetus, Pakicetus, Indohyus, and Kutchicetus. In addition to his work on fossil discoveries, Thewissen also studies modern bowhead and beluga whales in Alaska, focusing on their biology and the implications of this knowledge for management and conservation efforts. His research has been instrumental in deepening our understanding of cetacean evolution and the adaptations that allowed these mammals to transition from terrestrial to fully aquatic lifestyles.

<span class="mw-page-title-main">Christine Erbe</span> German-Australian physicist

Christine Erbe is a German-Australian physicist specializing in underwater acoustics. She is a professor in the School of Earth and Planetary Sciences and director of the Centre for Marine Science and Technology (CMST)—both at Curtin University in Perth, Western Australia. Erbe is known for her research on acoustic masking in marine mammals, investigating how man-made underwater noise interferes with animal acoustic communication.

Annemarie Surlykke was a Danish physiologist. She contributed significantly to bioacoustic research, in particular in the fields of insect hearing and acoustic communication, bat echolocation and insect-bat interactions. Graduated from University of Southern Denmark, employments at University of Tübingen and Aarhus University. From 1987 associate professor at University of Southern Denmark, full professor in 2011.

References

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  2. Brodie, Paul (1984). Macdonald, D. (ed.). The Encyclopedia of Mammals. New York: Facts on File. pp.  200–203. ISBN   978-0-87196-871-5.
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