IThe mating rituals were remarkably complex. When a male Chiriquí harlequin frog finds his mate, he climbs onto the female’s back, grasping his armpits with his forelimbs and hugging him. The females of this species were often twice as large as the males, and would remain in this mating lock for days or even months – depending on when the female was ready to lay her eggs. During this time, the male might give up eating and lose up to 30% of his body weight, but he was willing to wait.
It had been nearly 30 years since the last time a scientist saw this act. In 2019, with little fanfare, the genres were there It has been declared extinct.
Once upon a time, the Chiriquí harlequin frog (Atelopus chiriquiensis)Scientifically speaking, it was a frog, which can be found abundantly in moist highland forests Costa Rica and Panama, where the average annual precipitation exceeds 4,000 mm. In February 1994, when American biologist Eric Lindquist visited La Amistad International Park that connects the two countries, he heard them calling from everywhere, frantically counting 113 Chiriquí harlequin frogs within a 10-meter stretch of the creek.
“You kind of realize, ‘Oh my God, I might be getting ahead of some,’ he recalls, ’cause they’re just everywhere.”
Although classified as a frog, it does not look like one. It had smooth skin and was not warty. Its bright color – it can be green, yellow, rusty brown or gray, with lavender or red – warn predators of its toxicity. I preferred slalom on land to swimming.
Lindquist saw some of them “waving” their front limbs at others, possibly to avoid a fight, or as mating behavior. “I’ve also seen a female sign of a male, like, ‘Come on, come on to me,’ sort of,” he says with a laugh.
However, when Lindquist returned to the area just three months later, the tables were muted.
This decrease in numbers has also been observed in other protected sites and with other Mesoamerican frog species. In 1996, in the Fortuna Forest Reserve in PanamaAmerican herpetologist Karen Lips found 54 dead or dying frogs belonging to 10 species from four streams, when their numbers were abundant just a year ago. She described dying frogs ending up in their hands after a short struggle to escape and “freeze” the dead in their normal positions.
That year – 1996 – was the last year that the Chiriquí harlequin frog was seen anywhere in the world. He had disappeared so suddenly that any last attempts to save him via captive breeding were impossible.
Scientists found this sudden, large-scale disappearance of frogs in Central America puzzling, because it was occurring in protected forests and cannot be attributed to habitat loss. In 1999, lips landed on the culprit: a fungal disease that infects the frog’s skin that prevents it from breathing and regulates water levels in it, causing its heart to fail. Harlequin frogs are particularly sensitive to mushrooms because they prefer a cool, moist habitat that is conducive to their growth.
The disease, which is native to Asia and may have been inadvertently introduced elsewhere as part of the global wildlife trade, continues to threaten amphibian species. It is said to have destroyed more global biodiversity than any other disease ever recorded, declining 501 species of amphibians, 90 of which are presumed extinct in the wild.
But there is still a sliver of hope.
“At least some species of frogs have been found in Costa Rica again in places we thought they had disappeared, and some are found in new places,” says local biologist Federico Bolaño.
With encouragement, scientists continue to visit the known habitats of the disappeared frogs, hoping to find survivors. However, according to Jorge Rodríguez Matamoros, a conservationist in Costa Rica: “The new numbers tend to be very small, and the species are still fragile until extinction.”
Experts also believe that climate change may have weakened the frogs’ immunity or somehow changed how disease survives and spreads.
The loss is personal to biologists like Lindquist. “These frogs are a little special to me because they were everywhere,” he says. “And then they weren’t.”