Detroit Zoological Society jumps in to save critically endangered toad

Nearly 8,000 zoo-born Puerto Rican crested tadpoles released into the wild

A Puerto Rican crested toad (Detroit Zoo)
A Puerto Rican crested toad (Detroit Zoo)

On June 5, thousands of the critically endangered Puerto Rican crested toad tadpoles left Detroit for Puerto Rico's El Tallonal biological reserve as part of a federal program for amphibian restoration.

The Puerto Rican crested toad—a greenish brown pebbled amphibian with marbled golden eyes—is among half of the world’s known 8,030 amphibian species suffering from habitat loss, climate change, pollution and infectious diseases that ultimately lead to potential extinction.

The Puerto Rican crested toad, or Peltophryne lemur, can grow only 3 to 4 inches but has the ability to nearly flatten its entire body to fit into tiny crevices. Their small size makes it hard for Detroit Zoo visiors to spot, but underneath one of the naturalistic limestone structures, one might be able to see their large eyes and pointy, hooked noses peering out.

The 7,809 crested toad tadpoles will join the nearly 84,000 Detroit Zoo-born tadpoles released to the reserve over the past decade. However, 15 of the tadpoles will remain at the Zoo's National Amphibian Conservation Center for future breeding. 

To prepare the tadpoles for their journey, Detroit Zoological Society amphibian staff spent over six hours counting and packing each tadpole into padded and insulated shipping boxes. Heavy-duty fish-shipping bags were doubled up and filled with oxygen to keep the tadpoles safe and healthy.

After a 24-hour trip, the tadpoles entered their new home: a pond inside a heavily protected forest in Puerto Rico. This specific species is currently being monitored to determine if the captive breeding program successfully advances the wild population.

Director of the National Amphibian Conservation Center, Dr. Ruth Marcec-Greaves, said she believes these tadpoles represent hope for this critically endangered species.

“Many amphibian species, such as the Puerto Rican crested toad, are declining and would not survive in the wild without captive breeding programs," Marcec-Greaves said. "This release will significantly bolster the number of these toads in their natural environment."