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"Snot Otter" Sperm to Save Giant Salamander?

Cryopreservation may be the last chance for the hellbender, aka the snot otter.

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North America's biggest salamanders, hellbenders can grow as long as 2.5 feet (0.7 meter) (file photo).

 Photograph by Joel Sartore, National Geographic

-Hellbender sperm-cell tail, with characteristic "corkscrew" tissue. Photograph courtesy Dalen Agnew.

It may be a shot 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 northeasternArkansas to New York.

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The 2.5-foot-long (0.7-meter-long) amphibians have declined by 80 to 90 percent in most

of their traditional watersheds in recent decades, and now haunt only isolated pockets of 

southern Appalachia (see map), said Dale McGinnity, curator of reptiles at  NashvilleZoo.

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 addthe 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 agedindividuals—the amphibians likely live between 30 and 80 years, McGinnity said.

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 freezessperm 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 whythey'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 effortwith colleagues from Belgium's Antwerp Zoo and Michigan State University.

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A sort of "insurance policy" against extinction, the sperm will enable scientists to manage

hellbender breeding, according to team member Dalen 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 beweaker and more susceptible to disease.

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.

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.")

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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: the Chinese giant salamander 

(picture) and the Japanese giant salamander. (Read about a new giant-salamander 

 breeding center  that opened in July in Washington, D.C.)

"If we lose it, we lose a whole lot of evolutionary history," he said. "There's nothingsimilar to it."