Wildlife

Wildlife Wednesday: loss of bats to killer fungus linked to death of human infants

Plus: not so peachy jellyfish invade B.C., polar bears aren’t as old as once thought, and elephant seals can’t say no to a dinner bell

Little brown bats play an important role in ecosystems — and subsequenty, human health. (Photo: Froschauer Ann, USFWS)
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A new study led by University of Chicago researcher Eyal Frank has found that where bat numbers drop, infant mortality in humans rises. Frank and his colleagues examined what happened when white-nose syndrome, a fungal disease that kills bats, spread into new counties in the eastern U.S. They found that when bats were wiped out it was akin to “turning off the switch on biological pest control.” 

White-nose syndrome, first reported in North America in Upstate New York in 2006, kills an average of 70 per cent of bats that it infects. As it has spread steadily throughout the continent, one state or province at a time, bat populations have been left devastated in its wake. 

But the story doesn’t end with bats. Farmers are then forced to compensate for the loss of bats with a large increase in toxic pesticide use — sometimes by up to 31 per cent. Published in the journal Science, the study found that, as a result, infant mortality in the regions studied went up by as much as eight per cent — over 1,000 deaths.

This is yet more proof that human health is tangibly linked to that of the ecosystem we live in, and that bats are important for both these ecosystems and for our agriculture and health.

Bear twice removed

Polar bears are not as far removed from grizzlies as once thought. (Photo: Mario Hoppmann/NASA Goddard Space Flight Center)
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Polar bears occupy a “narrow ecological niche,” possessing traits that make them extremely well adapted to Arctic life. Many of these traits are what separate them from their closest relative, the brown bear. However, new genomic analysis by University of Copenhagen scientists, published in BMC Genomics, found that polar bears may have evolved some of the genes that separate them from brown bears as recently as 70,000 years ago — a mere blip on the evolutionary timescale.

The University of Copenhagen team analyzed the genomes of 119 modern polar bears, 135 modern brown bears, and two fossilized polar bears. One fossil sampled was a 100,000 to 130,000 year old jawbone from the Norwegian archipelago of Svalbard, the other the 70,000 to 100,000 year old skull of a juvenile polar bear nicknamed Bruno from Alaska’s Beaufort Sea.

Some traits that differentiate polar bears from grizzlies found in more recent samples that were not present in the two polar bear fossils, meaning they may have been selected in the last 70,000 years. “It was always assumed that when polar bears diverged from brown bears, they must have quickly adapted to the Arctic in one rapid evolutionary change,” says study co-author Michael Westbury. “However, our results suggest that may have not been the case, and the adaptation to the Arctic was a more gradual process.”

Life’s a peach

Peach blossom jellyfish are invading B.C. (Photo: OpenCage - opencage.info/Wikimedia Commons [CC BY-SA 2.5])
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The peach blossom jellyfish is no peach. The tiny creatures native to China have invaded fresh waterways around the world and are being spotted in the thousands in British Columbia, the species’ northern-most range in North America – so far. From 1990 to 2023, sightings of jellies ranging from a one to a few thousand have been recorded at 34 locations on Vancouver Island, the Lower Mainland and, more recently, as far inland as Osoyoos Lake, potentially posing a problem to local ecosystems by outcompeting native species. A new study out of the University of British Columbia, the first of its kind on peach blossom jellyfish in Canada, posits this species will continue to increase in numbers and likely expand its range in British Columbia as waterways warm due to climate change, predicting another 80 sightings in this decade alone. Of the jelly fish examined so far, all were males that shared the same genetic material, or clones. The study’s authors suggest that likely thousands of jelly clones originated from just one or a cluster of polyps, an early bottom-dwelling stage in a jelly’s lifecycle when can reproduce asexually, meaning the species is probably more widespread than we know.

There is such thing as a free lunch

A young male elephant seal hunts his unwitting prey at Ocean Networks Canada’s undersea laboratory at NEPTUNE’s Barkley Canyon observatory site. (Photo: Ocean Networks Canada)
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Googly eyes boggle out of the darkness, attached to a snuffling, trunk-like nose. It’s a young, male northern elephant seal — and he’s chasing down a sablefish for his dinner. Captured on camera by a deepsea observatory, clips like this are helping Oceans Networks Canada researchers learn more about fish foraging behaviour by these oceangoing seals. 

Just off the west coast of Vancouver Island, at a depth of 645 metres, the team had set up an array of high definition video cameras, acoustic imaging sonar and underwater sound emitters to study the effects of light and sound on deepsea fish and invertebrate behaviours. But the experiments drew an unexpected visitor — between June 2022 and May 2023, young male northern elephant seals were spotted at the site during seven distinct periods, providing the researchers an opportunity to observe the foraging behaviour of these large boiz. 

The researchers hypothesize that the sonar they had been using in their experiments attracted the young males, effectively acting as a “dinner bell” of sorts. They suggest the seals learned to recognize that the human-made noise indicated that food, such as sablefish, was in the area, then take advantage of how the experiment’s lights disturbed the fish so they could more easily tuck into their easy meal. The marine elephants pursued active swimming fish over stationary fish, and the team also observed that the young males made “infrasonic sounds” while they were foraging, although it’s unknown whether these apparent vocalizations were voluntary or involuntary.

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