Five Years After Hurricane Katrina, Alien Rodents Return

Five years afterHurricane Katrinawhacked down the population of the invasive, wetland-munching rodents in Louisiana, nutria have bounced back.

At the same time, some coastal marshes are rebounding too, because of a boom in Louisiana's nutria trappers.

(See"Hurricane Katrina Pictures: Then& Now, Ruin& Rebirth.")

The 2005 to 2006 trapping season, which runs from November 20 to March 31, yielded 168,843 nutria tails. The 2009 to 2010 season, by contrast, set a record: 445,963 nutria tails, according to state figures. Trappers hunt the rodents for money and discard their carcasses.

"The amount of animals harvested this past year is a result of economics in the area,"said Edmond Mouton, who heads theNutria Control Programwith the Louisiana Department of Wildlife and Fisheries in New Iberia.

Simply put, more out-of-work residents are out trapping the rodents, which are native toSouth Americabut were introduced to the U.S. as a fur species in the late 19th century.

The impact of the hurricane—which killed many nutria outright—was short-lived, Mouton added. (Related:"Katrina Weakened, But Didn't Wipe Out, Invasive Rodents.")

"They established several populations elsewhere, and some of the populations that were decimated… slowly became re-established,"Mouton said."It is a fairly resilient species and able to handle such catastrophes."

Eroding Gulf Coasts Losing Storm Barriers

Coastal wetlands protect inland areas from intense damage by storm surges. Yet due largely to oil-and-gas development,Louisianahas thehighest rate of human-induced coastal erosion in the U.S., according to the Texas-basedHarte Research Institute for Gulf of Mexico Studies.

Nutria only compound the problem by eating wetland grasses, which exposes the soils to erosion from the ebb and flow of the tides, Mouton said. Marshes that get converted to open water are"unrecoverable,"he said.

For every mile (1.6 kilometers) of coastal wetlands lost, storm surges increase by about a foot (0.3 meter), he noted.

Also unknown is the ultimate impact of the 2010Gulf of Mexico oil spillon wetlands."There is concern that {the oil spill} could exacerbate the already dire coastal-erosion issues in Louisiana,"Chris Macaluso, public information director for theCoastal Protection and Restoration Authority of Louisiana, told National Geographic News in May.

(Also see"Coast Pipelines Face Damage as Gulf Oil Eats Marshes?")

Money-Making Rodents

Harvesting the 15-pound (7-kilogram) nutria—which are widespread throughout the Gulf states—is one way humans can prevent wetland damage, the wildlife-and-fisheries agency's Mouton said.

To cull the Louisiana nutria population, wildlife managers implemented a program in 2002 that paid trappers four dollars for every nutria caught. (The fee increased to five dollars after Katrina.) (Read about alien invaders inNational Geographicmagazine.)

Since the program started, the amount of nutria-damaged wetlands has declined from more than a hundred thousand acres (40,450 hectares) to 8,475 acres (3,430 hectares), according to program statistics. (Seepictures of Louisiana's wetlands.)

"Not only has the number of acres been reduced but also the severity of damage,"Mouton said.

In an average year, trappers kill about 300,000 nutriain Louisiana.

"The only year they were down was post Rita and Katrina, and that stands to reason,"Mouton said."A lot of individuals that harvest nutria live along coastal areas, and they were impacted as well by the storms."

forNational Geographic News

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Pictures: Pea-Size Frog Found—Among World's Smallest

A newfound, pea-size frog,Microhyla nepenthicola,sits on the tip of a pencil.

One of the smallest frogs in the world, the species was spotted inside and around pitcher plants in Malaysian rain forests on the island ofBorneo (map), which is divided amongBrunei,Indonesia, andMalaysia.

(Seepictures of a hairy-nosed otter and other rare animals captured recently by camera traps on Borneo.)

The new species was announced Wednesday, but the frogs have been hiding in plain view for more than a century.

"I saw some specimens in museum collections that are over a hundred years old,"co-discoverer Indraneil Das said in a statement.

"Scientists presumably thought they were juveniles of other species,"said Das, a herpetologist atUniversiti Malaysia Sarawakin Malaysia."But it turns out they are adults of this newly discovered microspecies."

(Read aboutvanishing amphibiansinNational Geographicmagazine.)

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"Snot Otter" Sperm to Save Giant Salamander?

It may be ashot in the dark, but freezing sperm is one of the last chances to save the hellbender,North America's biggest salamander, conservationists say.

Hellbenders—also known as snot otters and devil dogs—have dwindled throughout their range, which once encompassed streams from northeasternArkansastoNew York.

The 2.5-foot-long (0.7-meter-long)amphibianshave declined by 80 to 90 percent in most of their traditional watersheds in recent decades, and now haunt only isolated pockets of southern Appalachia (seemap), said Dale McGinnity, curator of reptiles atNashville Zoo.

All of the states in the hellbender's range have listed the animal as a"species of special concern,"and the U.S. Fish and Wildlife Service is currently reviewing whether to add the hellbender to the federal endangered species list, McGinnity said.

The reasons for their decline is unknown, but it's likely environmental contaminants such as pesticides are harming the creatures via their highly permeable skin, he said.

To make matters worse, hellbenders don't seem to be breeding at all in the wild, he said, possibly because human-made pollutants containing synthetic hormones are damaging the amphibians' reproductive systems.

As a result, there are apparently no young wild hellbenders in existence, only aged individuals—the amphibians likely live between 30 and 80 years, McGinnity said.

(Seephotos of vanishing amphibians inNational Geographicmagazine.)

The hellbender's decline spurred an international team to collect sperm from some captive salamanders in September 2009 for cryopreservation, a common zoo practice that freezes sperm without damaging its cell membranes.

Though several zoos have put a"great deal of effort"into breeding the amphibians in captivity, none has been particularly successful, McGinnity added. It's unclear why they're tough to breed, but it may be that it's hard to replicate the exact temperatures of their home streams.

"For the first time, sperm was collected from a living salamander, cryopreserved, and brought back to life,"said McGinnity, who is involved in the sperm-preservation effort with colleagues from Belgium's Antwerp Zoo and Michigan State University.

A sort of"insurance policy"against extinction, the sperm will enable scientists to manage hellbender breeding, according to team memberDalen Agnew,a reproductive pathologist at Michigan State University.

For instance, scientists can use the stored sperm to crossbreed individuals, he said, to ensure that wild hellbenders are genetically diverse, he said. Genetic diversity is important because if closely related salamanders breed, their inbred offspring will be weaker and more susceptible to disease.

(See"Human Sperm Gene Traced to Dawn of Animal Evolution.")

Sperm-Filled Salamanders

Despite their hellish monikers, the"big, flaccid creatures"are actually"very mellow,"Agnew said.

This docile nature certainly helps scientists collect salamander sperm, which is"milked"out of a hellbender by rubbing it between the front legs and tail, said Nashville Zoo's McGinnity.

During mating season, no such coaxing is needed.

"Just by picking the animal up, {sperm} will come pouring out of the animal. ... You need to be ready,"the Michigan State's Agnew said.

(Watch aNational Geographic Channel video of herpetologist Brady Barr"kissing"a hellbender.)

Agnew also found that the hellbender sperm cell—like those of other amphibian species—boasts a ribbon of tissue encircling the tail. Magnified 40 times, it"almost looks like a corkscrew spinning,"Agnew said.

The winding tissue likely adds a jolt of horsepower to the sperm cell, he said. (Related:"Sperm Recognize 'Brothers,' Team Up for Speed.")

So far Agnew and colleagues used a unique"recipe"of preservation ingredients to keep hellbender sperm viable for six months—ideally, the sperm could be stored for hundreds of years.

Snot Otters Unchanged Since Dinosaur Days

Hellbenders haven't changed much since dinosaurs ruled the world, which puts the amphibians in nearly a class of their own, Nashville Zoo's McGinnity noted.

There are only two species related to the hellbender: theChinese giant salamander (picture)and the Japanese giant salamander. (Read about anew giant-salamander breeding centerthat opened in July in Washington, D.C.)

"If we lose it, we lose a whole lot of evolutionary history,"he said."There's nothing similar to it."

National Geographic News

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Giant"Terror Birds" Used Their Heads Like Hatchets

Phorusrhacids have been extinct for millions of years, yet the so-calledterror birdsjust got a bit more frightening.

The flightless birds stood up to ten feet (three meters) tall and had hook-beaked heads the size of horse heads. Now a new study has apparently deciphered how the birds used those fearsome skulls—employing a fighting style like that of legendary boxer Muhammad Ali.

Researchers used CT scans of terror-bird skulls and biomechanical computer models to conclude that the birds likely used a speedy, graceful, strike-and-retreat style, killing their prey with a succession of punishing, hatchet-like blows.

The technique probably landed the birds a top ranking in the food chain of prehistoricSouth America, according to the study, published August 18 in the journalPLoS ONE.

"South America was a strange and different place back then,"said paleontologistLawrence Witmerof the Ohio University College of Osteopathic Medicine.

"It was an island continent and had been so since around the time of the dinosaurs, so there was a lot of evolution that took place in its own microcosm,"said Witmer, who co-authored the new study.

After rising about 60 million years ago, terror birds evolved into at least 18 species, all of which disappeared by about two to three million years ago, around the time North and South America collided.

Because no living animals like the phorusrhacids exist today, terror bird behavior is something of a mystery.

(See also"Terror Birds: Predators With a Kung Fu Kick?")

Terror Bird Floated Like a Butterfly, Stung Like a Bee

To unlock clues to the terror-bird lifestyle, the international team looked to specimens ofAndalgalornis,a 4.5-foot-tall (1.4-meter-tall) terror bird that lived in northwesternArgentinasome six million years ago. (Related:"Largest 'Terror Bird' Fossil Found in Argentina.")

The scientists used CT scans to examine the architecture of the skull from the inside out, finding a structure far more rigid than that seen in most birds.

The data were used to create engineering-based, 3-D computer models, which revealed the stresses created when the digital skull was put through a series of biting, thrashing, and shaking movements.

Anatomy and biomechanics pointed to the same behaviors—those of an"outside fighter,"Witmer said.

"This animal had a hatchet-like skull that was very strong and rigid when being driven straight down into prey but was weak from side to side,"he explained.

"Consequently these animals weren't sluggers. They couldn't grapple with prey, couldn't handle those twisting movements.

"So these things were more like a Muhammad Ali, dancing around, using their speed and surgically precise jabs with that hatchet-like skull coming straight down over and over again,"he said."That's how they killed their prey."

Terror Bird: Latter-DayT. Rex

This system likely proved extremely effective—at least for some tens of millions of years—because the birds appear to have chopped their way to a rarefied role.

"The conventional dinosaurs went extinct,"Witmer added."But these terror birds were like avian dinosaurs which in many ways filled the ecological niche that predatory dinosaurs filled.

"T. rexwas a large, head-dominated, bipedal predator, and that's kind of what we're talking about with these terror birds—though both the birds and their prey were smaller than animals of the dinosaur era."

(Also see:"Seven of the Biggest Beasts of All Time.")

forNational Geographic News

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Pictures: Bushy-Bearded Titi Monkey Discovered

A new species of monkey with a red, bushy beard (pictured) has been discovered in theColombiansection of the Amazon rain forest, conservationists announced today.

A scientist first glimpsedCallicebus caquetensis—a type of titi monkey—in the 1960s. But political strife in the southern Caquetá Province (seemap) kept scientists away until 2008, when an expedition finally confirmed the bearded monkey as a new species. (See"New Monkey Species Found in Remote Amazon.")

The cat-size primate is"fascinating"because it mates for life, an unusual trait among monkeys, said expedition leaderThomas Defler, a primatologist at the National University of Colombia in Bogotá. Pairs are often spotted sitting on branches with their tails intertwined.

A typical Caquetá titi couple has a baby every year, and the father handles most of the infant's care, other than nursing, Defler noted. It's unknown why the dad does most of the work, but there's likely an evolutionary advantage, he said. (See morepictures of devoted animal dads.)

The discovery, funded byConservation International's Primate Action Fund andConservation International Colombia, was detailed online August 12 in the journalPrimate Conservation.

—Christine Dell'Amore

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Photos: Ten Most Wanted"Extinct" Amphibians

Last seen in 1989,Costa Rica's golden toad (pictured) is perhaps the most famous of the"lostamphibians"—virtually extinct animals that may be eking out an existence in a few scattered hideouts, conservationists say.

The toad—which likely disappeared due to a combination of drought and thedeadly chytrid fungus—is one of ten species that scientists most hope to rediscover during an unprecedented global search for"extinct"amphibians launched today. The ten were chosen for their"particular scientific or aesthetic value,” according to project leader Robin Moore, ofConservation International.

(Related:"'Extinct' Frog Found in Honduras, Experts Say.")

Led by Conservation International and the International Union for Conservation of Nature (IUCN)'sAmphibian Specialist Group, the effort will seek out a hundred such species but invest mostly in ten species of high scientific and aesthetic value.

The new project comes amid a steady decline in worldwide amphibian species, 30 percent of which are threatened with extinction, according to Conservation International. (Read aboutvanishing amphibiansinNational Geographicmagazine.)

Jason Rohr, a University of South Florida ecologist not involved in the project, applauds its goals.

"But I also discourageanyone from interpreting any new discovery of these species as previous scientific error or evidence that the particular species, or amphibians in general, have not 'croaked,'"he said by email.

"While a few remaining individuals or isolated populations is certainly better than a complete extinctions, this would unfortunately be a small victory considering the catastrophic, global loss of amphibians."

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Bats May Be Wiped Out by Fungus in U.S. Northeast

One ofNorth America's most common bats will go extinct in the northeastern U.S. within two decades if a deadly disease continues to spread unchecked, scientists warn in a new study. And other bat species—including the rare Indiana bat—may soon follow suit.

White-nose syndrome, first found in 2007 in aNew Yorkcave, is named for thewhite, cold-loving fungus that appears on afflicted bats' noses, wings, and ears.

The condition makes bats restless and disturbs their winter hibernation. Instead of sleeping peacefully, infected bats burn up their fat reserves, causing them to die at a staggering rate—almost 75 percent a year in affected colonies, research shows.

So far the syndrome is known to infect nine hibernating bat species, including the widespread and well-studied little brown bat. (Listen to bat calls.)

BiologistWinifred Frickand colleagues collected bat population data gathered over the past three decades from nearly two dozen hibernation sites in five states, and ran the data through population models.

Their analysis showed that little brown bat populations crashed when white-nose syndrome appeared in North America—perhaps introduced from Europe or another distant locale.

"We also found that if mortality continues the way we've seen it, the regional population of this bat ... will basically be gone from the landscape in 16 to 20 years,"said Frick, of Boston University and the University of California, Santa Cruz.

Bat Fungus Becoming a"Continental"Problem

The syndrome also seems to be spreading quickly into other parts of the United States, Frick noted.

During 2010 infected bats were found as far south and west asTennesseeandOklahoma(see a U.S. map). The fungus has also spread north to the Canadian provinces ofQuebecandOntario.

"This is quickly becoming a continental scale problem,"Frick said."We're not surprised by this, but we are distressed by it."

And, as the ailment gets a foothold in more places, it's impacting more bat species.

"We chose little brown {bats} because we had really good data, and because they were a very common and abundant species,"Frick explained.

"But it's reasonable to assume that other hibernating species will face similar dangers, because the fungus grows in the hibernation sites. And some of those species, like the Indiana bat, are already endangered species."

(Related:"'Drunk' Bats Fly Right—Discovery Surprises Scientists.")

There is no cure for the syndrome, though scientists are searching for ways to combat the disease.

Bat Extinctions Could Affect People, Too

Though the situation looks bleak for bats, humans also have cause for concern, Frick said. That's because the flyingmammalseat a lot of insects—such as mosquitoes—that damage crops, spread disease, and generally pester people.

(Relatedpicture:"Bats Use Same Aerial Tricks As Bugs.")

"All the bats affected are insect predators,"Frick explained,"and an individual bat can eat its own body weight in insects each night."

The bat-fungus research will be published in the August 6 issue of the journalScience.

forNational Geographic News

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