Danish researchers confirm narwhals and belugas can cross



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A team of researchers at the University of Copenhagen has compiled the first and only evidence that narwhal and beluga whales can reproduce successfully. DNA and stable isotopic analysis of an anomalous skull from the Danish Natural History Museum allowed researchers to confirm the existence of a narwhal-beluga hybrid.

For nearly thirty years, a strange-looking whale skull has collected dust in the collections of the Danish Natural History Museum. Now a team of researchers has determined the reason for the unique characteristics of the skull: it belongs to a narwhal-beluga hybrid.

A Greenlandish hunter shot the whale in the 1980s and was intrigued by its strange appearance. He therefore kept the skull and placed it on the roof of his toolbox. Several years later, Professor Mads Peter Heide-Jørgensen of the Greenland Institute of Natural Resources visited the settlement and immediately recognized the strange features of the skull. He interviewed the hunter about the anomalous whale he had thrown and sent the skull to Copenhagen. Since then, it has been stored in the Zoological Museum, part of the Natural History Museum of Denmark.

Based on the intermediate form of the skull and teeth, it has been suggested that the specimen may be a narwhal-beluga hybrid. "This is the first and only evidence in the world that these two species of Arctic whales can cross. Now, we do not provide the data that confirm that it is – it is indeed a hybrid, "says Eline Lorenzen, evolutionary biologist and curator of the Natural History Museum in Denmark, who led the study, which was published today in Scientific Reports.

Using DNA and stable isotope analysis, scientists determined that the skull belonged to a first-generation male hybrid between a female narwhal and a male beluga.

Bizarre set of chops

The skull of the hybrid was considerably larger than that of a typical or beluga. But the teeth were markedly different. While the narwhals have only one or rarely two long spiral fangs, the belugas have a set of uniform tapered teeth aligned in straight rows. The hybrid skull has a set of long, spiral, pointed teeth that are tilted horizontally.

"This whale has a bizarre set of teeth." The isotopic analysis allowed us to determine that the animal's diet was completely different from that of a narwhal or beluga – and it is possible that his teeth influenced his foraging strategy. hybrid was a resident of low, "according to Mikkel Skovrind, a doctoral student at the Museum of Natural History and first author of the article.

Researchers do not know what led the two species to mate, but suggests a new phenomenon:

"We looked at the nuclear genomes of a narwhal and a beluga, but we do not see any evidence of crosses for at least the last 1.25 million years of their evolutionary histories, so crossbreeding seems to be a very rare occurrence, or As far as I know, it has not been observed or recorded before, "says Eline Lorenzen.

Gems between museum collections

Lorenzen points out that she and her colleagues have used new analytical methods that have only recently been developed.

"There are some true gems in the world's natural history collections that can provide us with insight into the evolution and diversity of life on Earth. It is incredible when material – such as this skull, which has been stored in our collection for decades – can be revisited with new methodologies to gain new biological knowledge, "says Eline Lorenzen.

Mikkel Skovrind adds: "It would be interesting to find out if similar hybrid whales were found elsewhere."

FACTS:

  • By extracting DNA from the anomalous skull of the whale and comparing it to a genetic reference panel of narwhal and beluga, the researchers established the genomic affiliation of the whale.
  • Researchers have analyzed reference stocks of narwhal and beluga for stable isotopes and compared them with isotope values ​​of the hybrid skull. By measuring carbon and nitrogen concentrations in the bones, researchers were able to discern whether the whale diet consisted of food from the water column or the seabed. The isotopes demonstrated that the food choices of the hybrid whale were very different from those of any narwhal or beluga.
  • Narwhals and belugas are the only endemic toothed whales in the Arctic region. While they are close relatives of each other and approximately equal in size, the two species differ in their morphology and behavior. The narwhal is characterized by its long spiraled prey and has a grayish-brown pigmentation, while the belugas have two rows of uniform teeth and the adults are completely white. Narwhals are experts when it comes to food choice, and belugas are generalists.
  • The research is a collaboration between the Natural History Museum of Denmark at the University of Copenhagen, the Greenland Institute of Natural Resources and the Department of Anthropology at Trent University (CA).
  • The research is supported by the Carlsberg Foundation, the Young Researchers Program Villum Fonden and the Canada Research Chair program.
  • Access the search article in Scientific Reports On here

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