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Highlights from the Week's News

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They’ve Been Called an “Ecological Train Wreck”

November 26, 2023

Blue Whales Thriving Following Debt-for-Nature Swap

It looks to be a conservation success. About 50 years ago, the small island nation of Seychelles took steps to protect the Indian Ocean from whaling, and a new study shows that blue whales (Balaenoptera musculus) are spending months in the area where they had once been annihilated by Soviet hunters, according to the BBC. Humpbacks, fin whales, and blue whales filled the oceans at the beginning of the 1900s but were slaughtered by commercial whaling.

Two blue whales swimming side by side at Channel Islands National Marine Sanctuary  |  Credit: NOAA

Blue whales are the largest creatures known to have ever lived on Earth and can be up to 100 feet in length. Their tongues alone can weigh as much as an elephant and their hearts as much as a car.

Researchers from the University of Seychelles, Oregon State University, and Florida International University now think blue whales may be breeding around Seychelles after analyzing underwater audio recordings. The current number of blue whales is a tiny portion of what they once were, and they remain listed as endangered by the International Union for the Conservation of Nature.

Seychelles has protected about 154,000 square miles around its islands in a “debt for nature” swap in which more than $22 million of its debt was relieved in exchange for the country doing more to protect its oceans.

The study was published in the journal Endangered Species Research.

“Super Pig” Populations Set to Explode

They’ve been called an "ecological train wreck" and the most invasive animal on the planet. They’re roaming Canadian provinces close to the U.S. border, and their population is exploding.

Credit: Valentin Panzirsch/Creative Commons

Wild pigs (Sus scrofa) are called “super pigs” because of their size, ability to survive, and fertility. They aren’t native to North America but have been on the continent for centuries.  They are destructive to land by rooting up bugs and crops and spreading disease. Ruth Aschim, who led a study by the University of Saskatchewan four years ago, said in a recent statement that the pigs can cause soil erosion, degrade water quality, and prey on small animals.

According to Ray Brook, an expert on the pigs in Canada who spoke to the Associated Press, because feral swine have two litters of six piglets each year, they are difficult to eradicate. Several jurisdictions have banned hunting them because it makes them nocturnal and more wary.

Pigs were first brought to North America in the early 1500s by European explorers and settlers for food, and in the 1900s the Eurasian or Russian wild boar was introduced for sport hunting.  Now, feral swine are a combination of domestic pigs and wild boars.  In Canada, farmers were encouraged to raise wild boars starting in the 1980s, but the demand for them peaked in 2001 and some were set free. Their fur allows the animals to survive harsh winters.

The pigs were possibly eradicated in Minnesota about seven years ago, but they’ve been sighted about 20 miles north of the state border and might already be back. The wild swine currently inhabit Texas and the Southeast, and in the San Francisco Bay Area, more than two dozen of them ripped up soccer fields, lawns, and a park while looking for food.

Some states, like Colorado and Montana, have attempted to eradicate feral pigs.  In Colorado, the last known super pig was killed in 2018, according to the Denver Gazette, but there are concerns they could return.

How and Why Skunks Could Lose Their Stripes

Often, you smell them before you see them. Skunks have a pungent way of warding off predators, who recognize the animals' famous white stripes and know to avoid them for fear of getting sprayed. So scientists wondered, if there were fewer threats around, would a skunk lose its stripe?

Illustration of variations of markings  |  Credit: Tim Caro/University of Bristol

Probably, yes. A skunk’s stripe is a deterrent because predators associate it with their liquid defense. But in North America, some skunks are all black and some are nearly all white and the width of the stripe can range from thin to thick. So, what gives?

The variation in striped skunks (Mephitis mephitis) intrigued a team of researchers led by the University of Bristol, who studied museum specimens and cross-referenced them with their habitats where there were or weren’t known predators. They found that a diminished stripe correlated with fewer threats in the area—something called “relaxed selection,” when environmental conditions reduce the need for an important trait, in this case black-and-white fur. Conversely, if there were dangerous predators in their region, the specimens showed little variation in their coats.

Warning coloration in wildlife is not unique to skunks. Co-author Ted Stankowich, an evolutionary behavioral ecologist at California State University, Long Beach, told National Geographic that warning colorations known as “aposematism” are demonstrated by the red and black stripes of coral snakes or the brilliant colors of poison dart frogs.

There are other examples of relaxed selection in the wild. As ZME Science explains, some birds have evolved to become flightless when living danger free on remote islands, species of fish that dwell in caves have lost their eyesight, and certain mollusks have thinner shells compared to their kin that reside in more dangerous waters.

The study was published in the journal Evolution.

How “Koala Corridors” Could Help Save the Iconic Species

The Australian Bureau of Meteorology’s three-month outlook is predicting above average temperatures with below average rainfall for November through January. The forecast could indicate more bushfires amid an on-going drought, which is tough news for residents and wildlife—especially koalas.

Credit: Sardaka/Creative Commons

Despite being an icon of the Land Down Under, the marsupial’s numbers are declining in much of the country. Koalas are predicted to be extinct in the wild in New South Wales by 2050 due to wildfires and habitat loss from land clearing for logging and development. The World Wildlife Fund Australia reported alarming declines in koala populations, with a 50 percent drop in Queensland and a 62 percent drop in New South Wales since 2001.

The animals require large and connected areas to eat, move, and breed, so several groups of volunteers are creating “koala corridors” to give the creatures the space they need to survive. Organizations like the Bangalow Koalas work with local property owners to create a passageway through fragmented or burned land by planting trees so koalas, as well as other wildlife including endangered glossy black cockatoo, gliders, possums, and wallabies, can thrive.
 
The word koala is said to mean "no drink" in Aboriginal languages, and research has shown that the animals get water not only from eating eucalyptus leaves but also by licking water running down tree trunks when it rains.

So far, the Bangalow volunteers have planted over 336,000 trees on 119 properties. If all goes well, they will plant half a million by 2025 to meet their goal—and allow koalas to give those eucalyptus a lickin’.