The folk song “Frog is a-courtin'' tells the Frog's efforts to turn the sword and pistol over, begging the mouse. The Darwinian frog courtship ritual in the cool, temperate rainforests of southern South America is less conditional. What sets their hookups apart is the child custody arrangement.
Named after Charles Darwin, who found them in 1834 while exploring Chilean Island, Darwin, the Darwin frog takes a unique approach to parenting among amphibians. Men are ready to raise young people in the vocal sacs and lie down for themselves.
Adult Darwin Frogs are about an inch long and weigh less than a few paper clips. Frogs are thought to live in the wild for 15 years, but are highly susceptible to the effects of tyltidio Mycosis, a virulent amphibian disease caused by the tiltrid fungus. Since the 1990s, pathogens invading the superficial layers of the skin have been linked to the mass deaths of around 400 amphibian species, killing at least 90 people.
Chiloe Island was once a sanctuary for the frogs in Darwin, but the presence of Chytrid bacteria was confirmed two years ago. “This is likely a result of climate change that has made the local situation even more advantageous,” said John W. Wilkinson, a UK-based conservation biologist.
Within a year, more than 90% of the island's Darwin frogs were claimed due to the outbreak of Chytridi Omycosis. “They are dying within weeks of being infected,” said Ben Tapley, curator at the London Zoo, which specializes in endangered reptiles and amphibians.
Herpetologist and co-author of the guidebook Frog of the World, Mark O'Shea, “After contamination, habitat changes, fragmentation, destruction and predation by invasive species, the arrival of cyltridiomycosis could become the ultimate claws of many Darwinian community populations.”
In October, the species were on the verge of extinction, and the London Zoo organized a rescue mission and established a prisoner of war breeding programme to save frogs from being wiped out. “There's nothing like the Darwin frog,” said Dr. Tapley. “Their evolutionary distinctiveness is truly, really impressive.”
The variety is far apart
During breeding season, the male Darwin frogs used to attract women are quick and high-pitched whistles. “It's more creak-like, like the metallic that needs to be oiled,” Dr. Tapley said.
When a woman appears and the couple mates, she then lays up to 40 eggs in the litter of the leaves and flies away. Men protect the frogs in an all night that can last up to three weeks. Once the larvae reach a wiggling stage, the father scoops them up with his tongue. The embryo passes through the sac of his voice. His voice is an inflatable crease of the skin returning to the gro diameter. Within the deep folds of the membrane, tadpoles are safe.
After about two months, they remain silent during the incubation period, transforming from dull brown to bright green, and “birth” a colony of calmette through their mouth. The only other amphibian that behaves this way is the Northern Darwinian frog (rhyme rufum), which has not been documented since 1981 and is presumed to be extinct.
Frog's Box
The population decline was dramatic at Park Tantaco, a private nature reserve on the southern tip of Chiloe. A London conservationist has been charged with recovering a fungal-free frog for storage. Ultimately, they want to devise treatments to reduce the threat of fungi.
Fifty-five specimens were rounded up during the five-day expedition. To screen for possible contamination, skin swabs flew to a laboratory in Santiago, the capital of Chile. All but two frogs were cleared for a 7,000-mile journey to London. The 53 frogs were individually packed with ice and wet moss in climate-controlled transport boxes. A 2oz frog in a 120 pound box.
After moving to new excavations in London by boat, plane and van, the frog was moved to a biosecure room that reproduced the lighting, humidity and leaves of its natural habitat. “They were housed as breeding pairs to maximize genetic diversity,” Dr. Tapley said. “We plan to establish a studbook that will be used to maintain the racehorse pedigree.”
It was found that 11 men were carrying young people. Last month they spit out 33 hatching. Each measured two-half of the inch, the size of a pencil eraser.
The folk song frog met at his end with a lily white duck woman gull “swallowing him.” If London's prisoner of war Darwin frogs are reintroduced into the rainforest, they must seize chances with predators in southern Chile.
