Dec 9, 2012 2 min read

CLEVELAND (AP) – The Cleveland Metroparks Zoo will airlift nearly 5,000 crested-toad tadpoles to Puerto Rico for release into the wild.

The venture begins Monday in an effort to bolster an endangered species in Puerto Rico.

Hatched last week, the tadpoles are narrower than a pencil eraser.

Within two to three weeks their tails will drop away and they will morph into the familiar frog-toad conformation.

The tadpoles are small enough to fit on a dime.

Zoo conservation and science curator Kristen Lukas told The (Cleveland) Plain Dealer the program is a partnership of more than 20 zoos and is one of the few producing animals for introduction into the wild.

In the wild, tadpoles breed and hatch in short-lived pools left over from the rainy season. The zoo duplicates the process in three long glass tanks in a backroom at the RainForest exhibit.

Three breeding pairs are refrigerated to 66 degrees, then they are placed in the tanks. The temperature shift and moist environment duplicate the conditions that trigger mating.

Park managers and researchers from the University of Puerto Rico do a lot of important on-site work.

The Metroparks Zoo supports many non-captive species that visitors will never see.

Their 2011 conservation report said the zoo and partner Cleveland Zoological Society awarded grants that year for more than 90 field conservation projects in 39 countries around the world.

“Some of the funds raised when we built the African Elephant Crossing exhibit were set aside for field-conservation programs for elephants,” Lukas said.

One, in Tanzania, looks at how to improve areas in Africa where human and elephant populations overlap. Another underwrote a boat in Botswana so conservationists could track wild herds.