Wildlife Wednesday: belugas can change the shape of their melons to communicate

Plus even more whale news: grey whale die off declared over, using forensics to investigate humpbacks, a new species of orca, and a sad spate of right whale calf deaths 

  • Apr 10, 2024
  • 944 words
  • 4 minutes
(Photo: Brian Gratwicke/Flickr [CC BY 2.0 DEED]}
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Belugas — those stocky, dome-headed, all-white, Arctic (and sub-Arctic) whales with a perpetual smile that juxtaposes their worry-lined brows — just got even goofier. Researchers at the University of Rhode Island in the U.S. have observed belugas changing the shape of their melon — the fatty bulb atop their head used for communication and echolocation — during social interactions. By watching different pairs of beluga whales at aquariums in the U.S. and Canada, they identified five major shapes and labeled them as ‘shake’, ‘push’, ‘press’, ‘lift’ and ‘flat.’

A trained beluga demonstrating the ability to voluntarily change the shape of the melon. (Photo: Animal Cognition (2024). DOI: 10.1007/s10071-024-01843-z)
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The changes in melon shape usually occurred in an interaction between mates and mostly during line-of-sight events. While the researchers were not able to decipher the meaning of each shape, they noted that males changed their melon shape more often than females, and that the shake and flat patterns occurred most often during courtship rituals.

Good news for grey whales

(Photo: Andre Estevez/Pexels [Public Domain])
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For six years, grey whales have been dying en masse. A lack of food, collisions with vessels, and attacks from killer whales have combined to cause thousands of whale deaths in that period. But, now, the die off has finally been declared over, according to research published in PLoS One. 

“Between 2019 and 2023, what was really dramatic is the population was observed to have declined from 28,000 animals down to an estimated 14,000,” study author and University of British Columbia professor Stephen Raverty told CBC News. Six hundred and ninety whales were stranded in that period, the bodies sometimes washing up in rough shape — emaciated or scarred from attacks or collisions. 

Now, there are positive signs that the grey whale population is growing, with the number of calves born double that from the previous year. With that, there is a chance to rebuild the population. However, the dangers that caused the die off — a decline in nutritional abundance, killer whales, and shipping — still exist.


CSI: whales

(Photo: Glenn Edney/GRID Arendal [CC BY-NC-SA 2.0 DEED])
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Just like humans leave unique fingerprints on everything we touch, diving whales leave behind a unique print of their own. After a whale disappears below the ocean’s surface, a visible — if inconspicuous — circle ripples out from the dive point. Within this circle — termed a ‘flukeprint’ — there’s often concentrated DNA lingering in the whale’s wake, shed from the skin or exhaled from the blowhole. This makes a flukeprint the perfect spot to non-invasively collect environmental DNA, something the Ocean Wise Whales Initiative has been doing to learn more about whale relatedness and population dynamics, and can even to identify whales on an individual level. They have been collecting water samples to study the environmental DNA (eDNA) of Bigg’s killer whales, North Pacific humpbacks and B.C.’s endangered southern resident killer whales. The samples are being processed at the Pacific Enterprise centre in Vancouver, and a recent paper published in the journal Environmental DNA demonstrates the possibilities this fairly novel approach to whale research offers.

Same orca, new species

(Photo: Robin Gwen Agarwal/Flickr [CC BY-NC 2.0 DEED])
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New research from National Oceanic and Atmospheric Administration (NOAA) Fisheries in the U.S. has confirmed that two well known killer whales in the North Pacific Ocean are seperate species. Extremely widespread but long thought to belong to the species Orcinus orca, the different forms of killer whales in various regions were known as “ecotypes” rather than distinct species. However, biologists have increasingly recognized the differences between resident and Bigg’s killer whales (named for Canadian scientist Michael Bigg, who first described the differences between the two types). Residents are more family-focussed, preying on salmon and other fish. Bigg’s (or transient) killer whales roam in small groups, preying on other marine mammals like seals or whales. Depsite occupying many of the same Pacific Northwest waters, the two rarely if at all mix — a telltale sign of a different species. Now, scientists from NOAA and various universities have assembled genetic, physical and behavioural evidence that distinguishes transient and resident killer whales are separate species, genetically and culturally distinct. The two appear to have diverged more than 300,000 years ago, and are as genetically different as any killer whale ecotypes from around the globe. Next, the Taxonomy Committee of the Society of Marine Mammalogy will determine whether to recognize the new species in its official list of marine mammal species during its next annual review this summer.

Right whales in troubled waters

(Photo: NOAA NMFS Northeast Regional Office News 060408/Flickr [CC BY 2.0 DEED])
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Conservationists were expecting between 25 and 30 North Atlantic right whale calves so far this year. Instead, there have only 19, and three of those born so far are believed to have died. According to Oceana Campaign director Kim Elmslie, there are about 70 reproducing females in the total local whale population of 360. While stating the positive aspect of calves more born this year compared to only 12 last year, she find the “deaths of calves really distressing becauce that’s the future of the species.” North Atlantic right whales generally give birth of the coast of Georgia and Florida between the end of November and February, but face dangerous a journey along the eastern coast of the U.S. as they make their way up to Canada for feeding. “I’ve heard them called the urban whale because they do travel somewhat close to shore,” Elmslie told CBC News. “But along the whay they’re encountering all of these different vessels that are transiting the area and millions of lines worth of fishing gear between the U.S. and Canada. It’s very challenging for these animals.” Oceana Campaign are calling for further protections than the 2023 measure the federal government is opting to repeat this year. 

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