Wildlife

Wildlife Wednesday: The “wonderful net” protecting whales and dolphins from deep-sea brain damage

Plus: wolverine genome is sequenced for first time, Arctic fish species is found to produce antifreeze, dinosaur fossil discovered showing some skin and a pesky Canadian insect is feeling the heat

A "wonderful net" of blood vessels cradling cetaceans' brains allow them to swim without brain damage.
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When a whale or dolphin swims, the powerful arching of its back and downward thrust of its fluke force pulses of blood towards the brain. This kind of locomotion-induced blood pressure spike would cause brain damage in most mammals. So how do cetaceans get away with it?

New research from the University of British Columbia published in the journal Science may have the answer. While other animals such as horses have the ability to disperse galloping-induced pulses of blood pressure by breathing in and out, this option isn’t available to marine mammals. Instead, the new findings suggest special blood vessels that cradle cetaceans’ brains may protect them. 

Known as retia mirabilia, Latin for “wonderful nets,” many theories previously surrounded the exact use of these mysterious blood vessels. Now, the UBC scientists’ findings assert that the retia use a “pulse-transfer” mechanism to maintain a balanced blood pressure in the whale or dolphin’s brain during movement. 

The researchers were unable to test their hypothesis directly by measuring blood pressures in the brains of swimming whales or dolphins for technical and ethical reasons. Instead they used a computer model to test biomechanical data they collected from 11 species of cetacean. The model showed that a pulse transfer mechanism could reduce the strength of the pulses by up to 97 per cent. Wonderful indeed.

Wolverine insights

The North American wolverine is a species of special concern and an iconic Canadian animal. (Photo: Jo Stolp/Pixabay)
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A team of scientists have, for the first time, sequenced the whole genome of the North American wolverine — an iconic Canadian animal listed as a species of special concern. The researchers, including scientists from the University of Toronto and Wildlife Conservation Society Canada, sampled DNA from a male from the Kugluktuk region of Nunavut.

The sequenced genome provides a present-day genetic snapshot of the wolverine and can ultimately be used as a benchmark of its genetic diversity — one that can be compared with past and future wolverine genetic samples. By sequencing the genome the researchers have pinned down the physical location of thousands of new DNA sequences on the wolverine chromosome. This will allow improved estimates of the animal’s gene flow, inbreeding, relatedness, parentage and population size. 

As climate change continues to change the landscape of wildlife across Canada, another important benefit of a sequence wolverine genome is the improved ability to look at environmental adaptations and predict the future adaptive capacity of wolverine populations to climate change.

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Un-frozen fish 

In 2019, the variegated snailfish became the first polar fish reported to exhibit biofluoresce. (Photo: John Sparks and David Gruber)
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Typically found in the coolant reservoir of cars, antifreeze lowers the freezing point of water-based liquids to regulate vehicle temperatures. It turns out, however, that cars aren’t the only place you can find this solution.

Researchers from the American Museum of Natural History recently discovered a small fish off the coast of East Greenland containing high levels of antifreeze proteins. The variegated snailfish (Liparis gibbus) is commonly found in the Arctic, where ocean current temperatures regularly drop below zero degrees. An issue for most wildlife, this species of snailfish can withstand the freezing temperatures without turning into an ice cube thanks to the antifreeze flowing through their veins.

In 2019, the variegated snailfish became the first polar fish reported to exhibit biofluorescence, glowing green and red in the dark depths of Arctic waters. Now, researchers can add the unique ability to produce antifreeze to this intriguing species’ repertoire of skills.

Scientists have been aware of the presence of antifreeze proteins in fish since the 1970s, but this discovery has the highest manifestation of antifreeze proteins ever observed. While the finding has amazed researchers, it also raises red flags regarding how this fish will survive the threat of a warming ocean. Like many other cold-water dwelling species, more temperate waters may increase competition between the snailfish and species better adapted to warmer waters. Antifreeze may be life-saving now, but it will not protect the snailfish against climate change.

Thick skin

The exposed fossil — found sticking out of a hillside — is thought to be a complete skeleton of the massive duck-billed hadrosaur.  (Photo: Royal Tyrrell Museum)
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The fossil of a young duck-billed hadrosaur covered in scaly skin is the latest exciting discovery at Dinosaur Provincial Park in Alberta’s badlands. The exposed fossil — found sticking out of a hillside — is thought to be a complete skeleton of the massive plant-eating species.  

Entire skeletons are very rare, so palaeontologists are excited that this find will provide insight into what the dinosaur looked like and its anatomy. And the fact that it’s likely a juvenile could lead to a better understanding of how hadrosaurs grew and developed.

The cool find was made by Calgary-based biologist and dino enthusiast Teri Kaskie, who volunteers in a field school at the park run by Brian Pickles, a professor from the University of Reading in England. 

While bones are informative, it is the skin that makes this find doubly exciting. “When you find skin, or even better, internal organs, you can start to look at how these animals were when they were living and breathing,” Pickles explained in an interview with CBC News Calgary. 

Expert teams have now begun the slow and painstaking process of excavating the specimen while protecting the exposed fossil, which, they hope, will soon be displayed at the Royal Tyrrell Museum.

Bad turn for the army worm

Adult armyworm moths migrate to southern Canada from southern U.S. each summer. (Photo: gailhampshire/Flickr [CC BY 2.0])
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The true armyworm is known as a damaging agricultural pest in much of southern Canada. And while recent research from Western University suggesting the true armyworm is suffering due to increasing temperatures may be seen as good news, the reality isn’t as clear.

After spending the winter in southern U.S., adult armyworm moths migrate to Canada, laying their eggs on grasses and grains. When the eggs hatch, the larvae begin feeding on plants and crops. Often arriving in huge numbers, they can work through entire fields leaving little behind. However the new research shows that, as southern Canada continues to see an increasing number of days reaching 30 C or higher, larvae exposed to these higher temperatures ultimately produce fewer eggs as adults, with those eggs less likely to be fertile.

While a pest, armyworms are native to Canada. “These guys aren’t invasive,” says Cailyn McKay, the Western University Master’s student behind the research. “They’re just really bad when they come in large numbers. Birds and spiders eat them so their absence could have a ripple effect on other species.” 

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