Category Archives: Extinction

EXTINCT SPECIES: Study determines that Tasmanian tiger’s jaws were too weak to kill sheep

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Image of a shot thylacine and thylacine cubs via Wikipedia

Scientists, with the help of computer software, recently discovered that the now-extinct Tasmanian tiger, or thylacine, wasn’t the sheep-killer that ranchers made them out to be. Via the BBC:

This digital “crash test” revealed that thylacine’s jaws were simply too weak to have brought down an adult sheep.

“If a large carnivore – like a big cat for example – wants to take down a big prey item, it has to clamp down on its throat and suffocate it,” said Dr Wroe.

“A thylacine wouldn’t have been capable of this.”

The digital “crash test” revealed the weak points in thylacine’s jaws
Dr Wroe also explained that thylacine’s teeth were “built for slicing” rather than for crushing bone.

Comparing its skull performance with closely related, living species with known diets, the scientists were able to predict the likely body size of its prey.

“It probably fed on small animals, such as possums,” said Dr Wroe. “And its limited diet would have made it more vulnerable to extinction.”

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“The terrible loss of the thylacine signifies unjustified, negligent destruction of our native flora and fauna. It is a cautionary reminder of what we have lost, and that without urgent intervention other species will suffer the same fate.”

CONSERVATION: Scientists introduce non-native species in an attempt to save island ecosystem

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Image via Joachim S. Müller on Flickr.

Scientists are “re-wilding islands and even continents” in order to remedy sickened or damaged ecosystems. In one example of re-wilding ecosystems, scientists introduced a species of giant tortoise, from Aldabra Atoll in the Seychelles, to take on the ecological role that was played by a similar species of giant tortoise that went extinct on Ile aux Aigrettes, which is an island associated with Mauritius. More via Scientific America:

In 1965 the largely denuded 25 hectares of [Ile aux Aigrettes] were declared a nature reserve. But even in the absence of logging, the slow-growing ebony forests failed to thrive. Why? Because they had lost the animals that ate their fruit and dispersed their seeds. So in 2000 scientists relocated four giant tortoises from the nearby Aldabra atoll in the Seychelles, and by 2009 a total of 19 such introduced tortoises roamed the island, eating the large fruits and leaving behind more than 500 dense patches of seedlings. The team reported its results in April in the journal Current Biology.

For this tiny island, at least, rewilding appears to have worked. And that holds out hope for other restoration ecology projects in the midst of the sixth mass extinction in the earth’s history. In Europe conservationists have received €3.1 million to begin bringing bison, bovines and horses back to “abandoned” agricultural lands in places such as western Spain or the Carpathian Mountains. Ecologists have proposed repopulating parts of the U.S. with elephants, which would replace extinct mastodons. The Dutch, for their part, have already built what amounts to a Pleistocene park at Oostvaardersplassen, adding Konik horses and Heck cattle to replace extinct wild horses and cattle.

Of course, humans have a mixed track record when it comes to interfering in natural ecological systems—the introduction of the cane toad to Australia to manage other pests has resulted in a frog march of havoc across the continent. “There are no guarantees when trying to manipulate nature,” notes ecologist Mark A. Davis of Macalester College in Minnesota. Others argue that humans should fix what they have broken. “There is no place on this planet that humans have not interfered with, and it is time for us to become actively involved in engineering solutions,” says marine biologist Ove Hoegh-Guldberg of the University of Queensland in Australia. “There are no other options except extinction at this point.”

Continue reading this article at Scientific America.

IVORY-BILLED WOODPECKER: More evidence suggests that the ivory-billed woodpecker isn’t extinct

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The images, by Dr. Michael Collins, are purported to be of ivory-billed woodpeckers living in Louisiana. Dr. Michael Collins’s images are via Wildlife Extra.

An amateur birdwatcher claims that photographs and audio recordings, which he took, are of ivory-billed woodpeckers living around the Pearl River area of Louisiana. Apparently, his evidence has been dismissed by the professional ornithological community. Nonetheless, he defends the authenticity of his data and is publishing his work in the Journal of the Acoustical Society of America. Via LiveScience.com:

[Michael] Collins is an outsider to the ornithology community—he’s just a hobbyist bird-watcher—and few insiders take his work seriously. His evidence has been rejected by a string of ornithology journals – often, he says, without explanation.

And so he has turned to acoustics scientists to confirm his recordings. This month he will finally publish what he believes is solid evidence that ivory-billed woodpeckers live at Pearl River in the Journal of the Acoustical Society of America.

Collins, a researcher at the Naval Research Laboratory-Stennis Space Center in Mississippi, first started searching for the bird when a team of Cornell ornithologists captured putative footage of a specimen in Arkansas in 2005. That possible sighting, the first well-documented (though not definitive) human encounter since about 1940, made it onto the cover of Science Magazine. The birds were said to have lived at Pearl River in the past, so when Collins heard that they might still exist as a species, he decided to look for them there.

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The audio recordings, which he obtained in conjunction with the videos, also smack of the Lord God bird, which makes very distinct double knocks when pecking, and makes vocalizations somewhat like a blue jay’s and nothing like a pileated woodpecker’s. Collins used his mathematics expertise to construct sophisticated acoustical models of the bird’s vocalizations. The audio and video evidence combined, he says, give firm support to his claim that ivory-billed woodpeckers live at Pearl River.

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“Professional jealousy is a huge problem in the field of ornithology,” Collins said. “There are groups who have received a lot of funding to obtain conclusive data on these birds and haven’t managed to do so, and I’ve done it independently.” One such group, he said, is the Cornell Lab of Ornithology, the country’s leading center of ornithology research and the group who may have sighted the elusive woodpecker in 2005.

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The Cornell group, which Collins accuses of having exerted its influence to keep his work out of ornithology journals, commented briefly on his new acoustics paper.  ”Although we believe the evidence presented is inconclusive, we applaud Collins’s continued efforts to locate and document possible ivory-billed woodpeckers and to publish his findings for all to evaluate,” Kenneth Rosenberg, director of conservation science in the group, said.

You can read the rest of this article at LiveScience.com. More on Collins’s claims can be found at Wildlife Extra.

EXTINCT SPECIES: Man claims to have purchased Tasmanian tiger pelt for $5

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The image of Bill Warren with his Tasmanian tiger pelt was taken by Charlie Neuman. The other images below depict the tiger in captivity and as a hunted animal.

A man claims to have purchased a Tasmanian tiger pelt from a garage sale in San Diego for just five dollars, but the pelt, if verified, is worth thousands more. From the San Diego Union Tribune:

[Bill] Warren might turn a $5 buy into $70,000 after finding what appears to be the pelt of an extinct Tasmanian tiger at a garage sale.

Warren found the unusual looking animal skin in Rainbow in June. The owner had bought the skin some 30 years ago at another garage sale in Boston.

“I didn’t know what it was, and neither did she,” Warren said. But he had a hunch it was something interesting.

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“They’re a very rare item to come across,” said Andrew Snooks from Armitage Auctions in Australia.

Snooks said the auction house is negotiating with Warren to obtain the pelt. After the house confirms that the pelt is indeed a Tasmanian tiger, it will go up on the auction block.

Snooks said the last Tasmanian tiger pelt sold at the auction house went for $68,000, and a rug made from eight pelts sold for $260,000.

Of course, there is still the business of verifying the pelt. Warren sent photos of the animal skin to John Long, vice president of research and collections at the Natural History Museum of Los Angeles. Long responded by e-mail that it looked like a Tasmanian tiger, but only expensive testing could confirm it.

The Tasmanian tiger, or thylacine, Thylacinus cynocephalus, is a presumably extinct species of marsupial carnivore. It once ranged from Papua New Guinea to Australia and south into Tasmania, and “wild thylacines were present until the early 1900s; the last known captive specimen died in Hobart Zoo in 1936.”

The extinction of the thylacine is blamed on competition with the dingo, which probably arrived with humans thousands of years before. In more modern times, the targeted eradication of the thylacine on the island of Tasmania — the species’ last stronghold — helped doom the unique animal to extinction (although it may still exist in very remote regions of Tasmania).

The thylacine is an example of convergent evolution. It’s neither a tiger or a dog. Although it strongly resembles a dog, coyote, or wolf, it’s not related to these species, which belong to the family Canidae. The thylacine belongs to the family Thylacinidae, and they’re also marsupials, while dogs are placental mammals.

Images found here, here, here, here, here, and here.

CONSERVATION: Hunters, rich conservationists, and local farmers can help protect Africa’s wildlife

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[N]o matter how fecund nature is, humans are more so. With Africa’s human population set to double to 2 billion by 2050, new thinking is needed to preserve the continent’s remaining biodiversity.

Image: In order to protect the last remaining northern white rhinos (Ceratotherium simum cottoni) from poachers, conservationists must keep their horns filed down. Although “a slight recovery was recorded in 2003[,] when 30 [northern white rhinos] were counted[,] . . . by 2006 only four were left.” After the rhino’s last known stronghold—the Garamba National Park in the Democratic Republic of Congo—succumb to war and civil unrest, the remaining northern white rhinos haven’t been seen since. The individual below represents captive individuals that were translocated to Ol Pejeta in order to improve their fecundity. Image via Wikipedia

The Economist has an interesting piece on how economics can be a major driver of species extinctions—particularly when demand and value are high for animals or certain type of animal parts (e.g., poaching for medicinal purposes or poaching live specimens for the pet trade). The article begins by giving a somber assessment of the northern white rhino.
Certainly, if economics can destroy nature, then economics can also be used to save nature. For example, hunting is “a potential bonanza for local communities.” Therefore, as a product of that idea, the authors mention that anti-hunting efforts may hurt conservation efforts. The article also highlights another problem facing conservation efforts—human expansion—and briefly mentions how culture can be a factor in accelerating biodiversity loss, which is an interesting idea.

To save species, particularly in Africa, the authors don’t necessarily promote the fortress model towards conservation, but they offer several alternative ideas that seem to have success or potential for success. For example, (1) conservationists should place value on biodiversity; (2) the management of Africa’s national parks should be modernized; (3) the privatization of land through wealthy conservationists, local communities (i.e., community-based conservation), or organizations, with access to adequate resources (e.g., monetary, indigenous knowledge, international donors), may be successful at conserving wildlife and landscapes; (4) employing “‘non-use’ earnings, where large numbers of people around the world pay small sums to buy shares in African biodiversity not to use it, but simply because they believe its protection is important to the planet, may achieve conservation goals; (5) addressing social issues such as poverty, illiteracy, and alcoholism can reduce pressure on natural resources; and (6) “looking at wildlife, rather than shooting it” can be a model for successful conservation. Of course, the idea of sustainability looms over all of these ideas.

There’s another issue at play, and it’s more of a philosophical consideration, but it raises important questions nonetheless. Even if hunting, or any other type of wildlife management scheme can successfully boost wildlife numbers or achieve conservation goals, then humans are undoubtedly creating nature or merely socially constructing nature. Consequently, we’re not saving the wilderness as it’s typically idealized in our minds or the first nature before humans (it’s impossible to know what that exactly looks like). We’re either saving what we think nature and wilderness should be or we’re shaping nature, wilderness, landscapes, or ecosystems to better fit our agenda. Essentially, the ideas we determine are fit to achieve conservation goals will paint the picture of nature or have a direct impact on the “natural” landscape. Perhaps, chewing over the idea of a socially constructed nature when considering conservation goals is meaningless, since nature has been, and will continue to be, socially constructed. Via The Economist (emphasis added):

ONLY eight specimens of the northern white rhino are left alive on the planet, and they are all in captivity. The handful that remained in the wild in Congo have not been seen in years; they are almost certainly dead. A final effort to save the sub-species earlier this year saw four northern whites shipped from a zoo in the Czech Republic to the Ol Pejeta conservancy on the Laikipia reserve in Kenya.

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[T]he chances of saving the northern white are remote. Short of re-engineering it from frozen samples in the future, the best hope of preserving its genetic stock is to breed the last individuals with southern whites. That means the end of a creature that has probably been distinct for a million years. Indeed, the decline of the African rhino—which includes the black rhino as well as the white—is among the sorriest and most instructive tales in conservation.

When President Theodore Roosevelt came to east Africa in 1909 an estimated 300,000 rhinos roamed the region. Now there are perhaps 2,000. The problem is not that the rhinos are half-blind, lumbering, and often infertile—which they are. It is economic: the ornamental and medicinal value of rhino horn makes it hard for the rhino to pay its way alive.

The value of rhino horn in China, ounce for ounce, is higher than gold. It is likely to keep rising with an ageing population; in Chinese medicine the horn is ground into a powder to alleviate fevers and pain, particularly for terminally ill patients. With more Chinese contractors working in Africa, the risk of poaching seems to have increased. Market forces are insistent. Even at Ol Pejeta, which is protected by electric fences and armed guards, the horns of the four northern whites have had to be filed down to limit the risk of poaching. An inside job at one private ranch in Kenya last Christmas saw a rhino killed and its horns hacked off. The Kenya Wildlife Service later tracked down the culprits and recovered the horns, along with $8,500 in cash the poachers had been paid, with the balance payable on delivery. Sold in 10g increments in Guangzhou, the seven kilos of horn would be worth $250,000.

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Some countries have had success with hunting. Namibia, for instance, has increased the absolute numbers of its game animals by allowing oryx, hartebeest, kudu and springbok to be hunted and harvested as high-protein low-fat meat for regional supermarkets. Peter Lindsey of the University of Pretoria argues that animal-rights groups are denying Africa the wise use of its elephants—whose ivory is a resource, in his view, because elephants’ fertility suggests it could be harvested sustainably. He reckons trophy-hunting in Africa is worth $200m a year: a potential bonanza for local communities.

But animal-rights organisations like the Born Free Foundation object to hunting on ethical grounds. They argue that many hunters who start with gazelles end up going after predators, often illegally. And the money does not reach the locals: much of what is generated is taken offshore. The debate is bitter. The pro-hunting lobby complains that animal-righters have a lot of money to splash around, and are even writing legislation in several African countries in return for donations to government wildlife services. Hunters say their activities complement tourism: their clients are happy to stay in shabby, dusty places as long as they get their kill. But the bloodthirsty history of big-game hunting in Africa means that hunters still need to show that they have an economic value.