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Cane Toads, Blue Whales, Red Wolves and Other Updates from the Brink

The views expressed are those of the author and are not necessarily those of Scientific American.


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cane toadPeople often ask me, “How can you write about endangered species all the time? Isn’t it depressing?” Sure, it can be, but not as depressing as the sheer number of stories that I don’t get to write about. So let’s catch up on some of the stories that should have made headlines this month.

First on our list, let’s look to Australia, where endangered species are being taught not to eat cane toads (Bufo marinus), the toxic, invasive species that has famously wreaked havoc on the continent’s ecology. Scientists are using a technique called taste aversion therapy, which teaches animals that potentially dangerous foods don’t taste good or will make them sick. I first wrote about this back in 2010, when the technique was being tested on northern quolls (Dasyurus hallucatus), which, like many other native species, have an annoying tendency to die when they try to eat cane toads. Scientists for Western Australia’s Department of Environment and Conservation say they have now tested taste aversion—with positive results—on quolls, dingoes (Canis lupus dingo) and unnamed snake and lizard species. If rolled out further, this could help native species recover from the effects of the toxic cane toad scourge.

Further south, new research published in Molecular Ecology finds more questions than answers in a study of blue whales (Balaenoptera musculus). The research revealed that the pygmy blue whale subspecies (B. m. brevicauda) that normally inhabits Australian waters has been found in the Antarctic, where it has sometimes hybridized with the Antarctic subspecies (B. m.intermedia). The researchers don’t know yet what caused this alteration in habitat but theorize it could have been caused by climate change (with the Australian whales seeking cooler waters) or by changes in ecology brought about by 20th-century whaling.

Sticking with the seas, the two populations of false killer whales (Pseudorca crassidens) off the coasts of Hawaii gained greater protections this month. The National Marine Fisheries Service declared these dolphins endangered in Hawaii and issued new rules about long-line fishing which should protect them from accidentally being caught on fishing lines. Other populations of this species worldwide are not currently endangered.

Moving inland, North Carolina has curbed nighttime coyote hunting after five rare red wolves (Canis lupus rufus) were shot and killed. Red wolves are critically endangered and were once extinct in the wild. The 100 or so animals that live in North Carolina all stem from a captive breeding program that re-released wolves into the state back in 1987. Both coyotes and red wolves are nighttime hunters, which reportedly led to fatal cases of mistaken identity.

northern spotted owlOn the opposite side of the country, the Obama administration has doubled the critical habitat for the controversial northern spotted owl (Strix occidentalis caurina). This reverses a decision from previous administration and puts recovery plans for the owls back in line with what was originally established in 1994. The logging industry has long opposed most efforts to protect the northern spotted owl.

In Arizona, the population of another controversial species, the Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis), is holding steady at 214 animals. Plans to protect the squirrel have been assailed by some citizens and government officials as “too expensive.”

Also holding steady a few continents away: vultures. More than 99.9 percent of the birds in India and Nepal died over the past two decades because of a veterinary drug called diclofenac, which does great things for livestock but sends any vultures that eat the bodies of treated animals into immediate renal failure. Diclofenac was banned in 2006 and now the populations of at least three species—long-billed (Gyps indicus), slender-billed (G. tenuirostris) and white-backed vultures (G. bengalensis)—are stable and might finally be starting their road to recovery, according to a study published in PLoS One. They still have a ways to go, as numbers remain low and the drug is still used illegally, but it’s a start.

Photo: Cane toad by Rob Barber via Flickr; used under Creative Commons license. Northern Spotted Owl by John and Karen Hollingsworth/USFWS

John R. Platt About the Author: Twice a week, John Platt shines a light on endangered species from all over the globe, exploring not just why they are dying out but also what's being done to rescue them from oblivion. Follow on Twitter @johnrplatt.

The views expressed are those of the author and are not necessarily those of Scientific American.





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