Although Brookfield Zoo in Brookfield, Ill., was closed to the public, animal care staff were still dedicated to helping efforts increase the population of the critically endangered Togo slippery frog, once thought to be extinct in Africa.
The species is found in only two isolated regions in Ghana, and along the border of Togo and Ghana—areas that total less than four square miles. Unusual for its large eyes and large back legs, the frog grows to only about 3.5 inches. It spends 90 percent of its life in fast-flowing water, which is essential to its breeding success. Its evolutionary distinctiveness and global endangerment have made conservation of the Togo slippery frog a top priority. A very shy species, it is closely related to the largest frog in the world—the Goliath frog, also from Africa.
Thousands of miles from Africa, in a behind-the-scenes area at Brookfield Zoo’s Swamp exhibit, animal care staff has created an environment it knows to be ideal for successfully breeding these elusive frogs. Zoo staff has also made surprising discoveries about the species, including the frog’s unusual, high-pitched mating call that can be heard under crashing waterfalls, and a “sucker-disk” on its belly that provides traction in fast-flowing water.
“This project has been particularly satisfying because we knew virtually nothing about this frog when we began, and have learned so much along the way,” said Andy Snider, curator of herps and aquatics, for the Chicago Zoological Society, which manages Brookfield Zoo. “We hope the success we are having in breeding the species in managed care, will one day help the wild population.”
In 2015 and 2016, two small populations of the species were discovered in Togo streams by the organization Pangolin Conservation. Soon after, a small group of tadpoles was sent to Brookfield Zoo where a breeding program began with the goal of maintaining a sustainable population in managed care. The breeding-program population would save the species from extinction if the frogs became threatened by catastrophic conditions in the wild.
Since little research has been done on how to care for the species, CZS staff created a husbandry plan based on similar, predominantly aquatic frogs. The tadpoles were divided into two groups—each group was placed in a habitat that mimicked a separate waterfall and pool system of their native environment.
Staff was successful in bringing 11 tadpoles to adulthood. Since the launch of the breeding program at Brookfield Zoo, more than 200 metamorphosed juveniles have been produced from the initial group of frogs, although not all of them survived. In addition, several dozen tadpoles hatched recently at Brookfield Zoo. Specimens will eventually be sent to other zoos in North America and Europe, an insurance policy of sorts in case one facility’s specimens suffer a setback. “It’s never good to keep all your eggs in one basket, so to speak,” said Snider.
Now, the techniques developed by CZS animal care staff are being used to help set up a conservation breeding facility for the species in Ghana. The Zoological Society of London (ZSL)—the international conservation charity behind London and Whipsnade Zoo—is also providing their expertise. A former ZSL EDGE (Evolutionary Distinct and Globally Endangered) Fellow is leading the development of the project. Now based at the conservation charity Herp-Ghana, he was previously part of ZSL’s EDGE of Existence program.
“It’s great to see that a prior EDGE Fellow is leading the way to support the long-term conservation of an important EDGE species—this is exactly the purpose of the program,” said Ben Tapley, curator of reptiles and amphibians at ZSL. “And of course, conservation breeding programs in zoos play an essential role in helping to further the understanding of the natural history and husbandry techniques required to grow populations of such threatened, yet fascinating, amphibians like the Togo slippery frog. The project and engagement with CZS are really positive steps for the species.”
What remains of the small wild population is at risk due to habitat degradation caused by farming, logging, and mining. In addition, Togo slippery frogs are severely hunted for the bushmeat trade because the meat of the frog is high in protein.