Oakland Zoo’s push to save Puerto Rican crested toad


The East Bay’s newest celebrities are mottled, wart-covered bug eaters with bulging yellow eyes, Carolyn Jones writes in this article for The San Franciso Chronicle.

At the Oakland Zoo, it was love at first sight.

The zoo is among the few in North America selected to breed the critically endangered Puerto Rican crested toad. Nineteen of the rare amphibians arrived a few weeks ago for unlimited crickets, rest and mating – a process biologists hope will result in thousands of tadpoles being shipped to Puerto Rico by this fall.

“These toads aren’t just ambassadors. Their offspring are going back to the wild to repopulate the species,” said the zoo’s zoological manager, Margaret Rousser. “It’s a huge weight on our shoulders. It keeps me up at night. … But what an honor.”

Puerto Rican crested toads are bumpy, lemon-size creatures with bony ridges on their foreheads and upturned noses. Their skin is a whirl of brown, yellow and green. The females hop after crickets. The males, which are smaller, sit quietly until the crickets come to them. Both burrow in the mud.

For millions of years, the crested toad hopped throughout Puerto Rico, eating snails and bugs and croaking away happily in the Caribbean nights. As Puerto Rico’s only native toad, it was a common sight in the island’s ponds and forests.

Puerto Rico trouble

Then, a century or so ago, sugarcane farmers imported the giant cane toad from South America to eat parasites that were gnawing at the sugarcane.

The cane toad was very successful. So successful, in fact, it bred wildly and crowded out the smaller, less voracious crested toad. Meanwhile, the ponds favored by crested toads were gradually drained for farming and development, leaving the crested toad without many options. By the early 1960s, scientists thought the crested toad had vanished forever.

But then, in 1984, biologists made a surprise discovery: A few of the toads were hopping around the Guanica National Forest, a dense and shady subtropical woodland on the southern remote coast of the island.

A survival plan

With that, the crested toad became the first amphibian to receive a species survival plan by the American Zoological Association.

These days, the crested toad has plenty of company. Because of the lethal fungus chytrid, about a third of all frog and toad species worldwide have died out or are close to it. Most zoos in North America are participating in some form of amphibian rescue, either breeding, studying or giving special care to their slimy friends.

At the Oakland Zoo, the crested toads – born at zoos in Cleveland and Canada – live in glass terrariums in a quarantined lab. For now, the toads are resting and eating, but in the fall they’ll embark on a highly regimented mating ritual that involves hibernating in a wine cooler and then emerging, amorous, into a simulated rain forest.

The tadpoles – hopefully, thousands of them – will be double-bagged, stored in an insulated box with a heating pad, and shipped overnight to Puerto Rico, where scientists will release them at five sites around the island.

So far, the breeding program seems to be working. Anywhere from 300 to 3,000 crested toads now live in protected ponds in Puerto Rico, apparently withstanding cane toads and chytrid without much trouble, said Diane Barber, ectotherm curator at the Fort Worth Zoo, who’s overseeing the crested toad recovery plan.

“It’s not a lost cause at all,” she said. “As long as we’re able to set aside habitat for them, they’ll do fine.”

About 15 zoos in North America are breeding crested toads, a difficult task because crested toads require space and specialized treatment, and because the toads are off-limits to the public they don’t generate revenue for the zoos. It’s mostly a labor of love.

“It’s really great the Oakland Zoo stepped up,” Barber said. “It takes a lot of resources to put crested toad offspring out there, but it’s extremely critical to this species’ survival. It helps put a halt to the worldwide amphibian decline.”

For the original report go to http://www.sfgate.com/science/article/Oakland-Zoo-s-push-to-save-Puerto-Rican-crested-5194453.php

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