Thursday, 25 October 2018

Frogs Are Disappearing, What Does That Mean? - via Herp Digest

For ages, they have been symbols in human culture — of fertility, gastronomy and now the alt-right movement. But these noble amphibians are declining in numbers.


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Banded bullfrogs, native to Southeast Asia (and not yet endangered), on their thrones of chanterelle, lobster and shiitake mushrooms.
Photo Credit Photograph by Kyoko Hamada. Styled by Victoria Petro-Conroy

By Ligaya Mishan, 10/18/18, New York Times Style Magazine

THE DUSKY GOPHER FROG, once endemic to the longleaf pine savannas of Mississippi, Alabama and Louisiana — and now listed among the 100 most endangered species on earth — is tiny, dark and warty.
 
The creature is often described as both secretive and shockingly loud, with a rumbling, back-of-the-throat mating call that is uncannily close to the human snore. It hides from the sun almost its whole life, finding shelter in burned-out tree stumps. And although it’s armed against danger (its glands secrete poison), in the presence of a predator, the three-inch-long frog lifts its front legs to cover its eyes, like a child pretending to be invisible: You can’t see it if it can’t see you,

As of 2015, around 135 dusky gopher frogs were estimated to remain in the wild, mostly at a single pond in Mississippi, their breeding sites fragmented by new roads and the timber industry. The fate of the species may lie in the hands of the Supreme Court, which, as it begins a new term in October, will consider as its first case Weyerhaeuser Co. v. United States Fish and Wildlife Service. The lawsuit concerns the government’s designation of privately owned land in Louisiana as a critical habitat for the endangered frogs, setting property rights (and a potential $34 million loss in development value for the $27 billion Weyerhaeuser Company) against environmental conservation.

One study estimates that since the 1970s, around 200 frog species have disappeared, with a projected loss of hundreds more in the next century. Frogs are under threat on nearly every continent: from the French Pyrenees to the Central American rain forests to the Sierra Nevada in California. Some species, like the dusky gopher frog, have been depleted by human encroachment on their habitats. But the decimation that started 50 years ago was largely the work of the chytrid fungus Batrachochytrium dendrobatidis, which thickens a frog’s skin, hindering the animal’s ability to absorb water and oxygen and to maintain a balanced flow of electrolytes, leading to heart failure. Once infected, entire populations can collapse in a single season.

No one knows exactly how the disease spread, but it was likely carried unwittingly by humans from one country to the next, or by the female African clawed frogs that were shipped around the world for laboratory experiments and, until the early 1970s, hospital pregnancy tests. (In the test, a frog was injected with a woman’s urine, which, if she was pregnant, would contain an ovary-stimulating hormone that caused the frog to lay eggs.) Live frogs, potential carriers of the disease, continue to be moved across borders into nonnative habitats; in the first decade of the 21st century, the United States imported nearly 48 million pounds of them, some destined to become exotic pets, others winding up on dining tables.

More than three billion frogs are eaten worldwide each year, some 4,000 tons by the French and half that by Americans, who tend to prefer them patted with flour and sautéed in browned butter. These are mostly farmed frogs and thus not as vulnerable to extinction, but the circumstances in which they’re bred and exported may contribute to the spread of disease. And while in some parts of Asia the whole frog — minus the skin, which contains toxins — is submitted to the pot and boiled for soup, in many cases only the hind legs are used for food, meaning the bulk of the body goes into the garbage.


It’s an ignoble end for an animal that, despite its diminutive size, has held an exalted role over the ages in almost every culture. Frogs have been revered as emissaries of the divine (because of their regenerative powers) and feared as witches’ familiars, noxious and baleful. They have also been beloved as our stand-ins, infiltrating the stories we tell about ourselves, appearing as tricksters and fools, pompous kings and yearning commoners. Their value isn’t merely symbolic: Their croaks were the music in hundreds of early Japanese verses, until the 17th-century Japanese poet Matsuo Basho gave them physical presence — and comic power — in the famous 1686 haiku: “Old pond / Frog jumps in / Water-sound.” Their omnipresence in our fables speaks to their centrality in sustaining the world around us. In science class, they are our introduction to biology, dissected to reveal life’s inner mysteries. Toxins in their skin may yield new antibiotics and painkillers.

More fundamentally, frogs are linchpins in the ecosystem, both predator and prey. And they are our watchmen, keeping vigil over our ponds, marshes, lakes and streams, our meadows and our woods, the quality of our water and our air. “If they go silent, there could be bad stuff happening,” says Christopher J. Raxworthy, a herpetologist at the American Museum of Natural History in New York. Like honeybees, whose colonies began to collapse en masse across the United States a decade ago, frogs are portents of the greater ills that could befall our environment — and us.

AS AMPHIBIANS, frogs lead double lives, in water and on land, starting out as tadpoles equipped with gills and tails, which are reabsorbed into their bodies as they grow lungs and limbs. The seasonal emergence of frogs prophesies rain, essential for crops and survival, and their role in spring’s awakening may explain why early Christians used images of them to celebrate resurrection. In frogs’ prodigious fertility — they lay tens of thousands of eggs each mating season — the ancient Egyptians saw abundance; the goddess of fertility, Heqet, is often depicted as a frog-headed woman, and the hieroglyph for the numeral 100,000 was a tadpole. But too many frogs, and they become a plague.

It’s this duality that has ultimately endeared them to us, for these creatures hold out the promise of human transformation, the ability to shed an ugly skin and reveal a hidden self. Part of the appeal of Kermit the Frog is his status as an Everyman: small, far from powerful, but pure of heart. Even his latter-day counterpart Pepe the Frog was originally a good-natured slacker, first drawn in a 2005 comic strip by Matt Furie, before being co-opted as a symbol of the alt-right movement, whose members seem to have conflated Pepe with Kek, the frog-headed Egyptian god representing the darkness before the world was born. (Furie killed off Pepe last year to prevent further misappropriation.)

Another cultural invasion of frogs occurred last winter, when one of the most downloaded smartphone apps in Asia was Tabikaeru (Journey Frog), a game featuring an amphibian that spends much of its time reading in a cozy hut, then wanders off for an indeterminate amount of time, occasionally sending home snapshots. This unfolds without any human input; players do little more than pack food for the frog’s journeys and pine for the little nomad to come back — a comforting inevitability, as kaeru, the Japanese word for frog, sounds almost exactly like the word for return. Tabikaeru is particularly popular in China, where the characters for frog and child are both pronounced “wa” in Mandarin, with only a slight difference in tone.

BUT THESE VIRTUAL FROGS may soon be all we have left. The rate of decline is particularly startling given that, until now, amphibians have outlasted most of life on Earth. “They’re survivors,” says Jennifer B. Pramuk, a herpetologist and animal curator at the Woodland Park Zoo in Seattle, Wash. Their ancestors evolved some 350 million years ago, and they have persisted through three global mass extinctions, including the Permian extinction 251 million years ago, which is known among scientists as the Great Dying because of the number of species lost: an estimated 80 to 96 percent in the oceans and 70 percent on land. Frogs — which separated from salamanders and emerged as a distinct order, Anura, between 240 and 275 million years ago — have been resilient, but their permeable skins are highly sensitive to changes in water quality and temperature.

When we grieve over frogs’ loss and the global degradation it suggests, we’re also mourning a kind of strange, singular natural beauty. Among those now extinct is the golden toad, of which the males were orange-skinned and bright as flame, once prolific breeders in the Monteverde cloud forest of Costa Rica. In 1989, a single male was counted. The next year, there were none. The southern gastric brooding frog, indigenous to the mountains of Queensland in eastern Australia, thrilled herpetologists with its unusual reproductive system: Females swallowed their eggs, which hatched in the stomach, only to be vomited into the world as fully formed froglets. The creature’s final appearance was in 1981.

Conservation efforts have succeeded in reviving a few species. Not long after the Kihansi spray toad, sunny yellow and smaller than a postage stamp, lost its home in the misty wetlands of Tanzania to a hydroelectric dam in 2000, 499 of them were airlifted to the Bronx Zoo. Within three years, only two toads were left at the original Tanzanian site. But by 2010, the rescued toads had spawned a thriving 4,000-strong population at the Bronx Zoo and the Toledo Zoo in Ohio; 2,500 were reintroduced to Tanzania two years later. Zoos may be the key to frogs’ survival, not only nurturing but proselytizing for them, so that a charmed public recognizes their worth.

Without frogs as a predator, mosquitoes and other invertebrates, themselves carriers of disease, will multiply. “It’s another chink in the armor of the ecosystem,” Pramuk says. Gone, too, will be the spring choruses, frogs calling for their mates. Pramuk still remembers when she finally made it to the Costa Rican cloud forest in 1995, six years after the sighting of the last golden toad, one of her favorite species, which she’d studied only on paper. She had hope: Sometimes amphibians thought extinct have suddenly reappeared. “You always think, ‘Maybe it will show itself to me,’” she says. So she stood and waited, listening to the silence. Frogs are the heralds of dusk, their evening song laying the day to rest. Without them, it is only night.

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