Right now, we’re watching over eggs from golden mantellas, Mantella aurantiaca, and black-eared mantellas, M. milotympanum, both critically endangered species, and from blue-legged mantellas, M. expectata, an endangered species (shown above). Some of the black-eared mantellas have hatched and turned into tadpoles.
“These are rare, beautiful frogs,” says senior aquarist Stacy Wozniak. “Their forest habitats have been decimated by logging and fires, and by an expanding human population that is clearing more land on the island for subsistence farming and cattle ranching.” Between habitat destruction and unsustainable land use, it’s a lose-lose situation for frogs and people, he adds.
Some of Shedd’s original mantella frogs came from a sister aquarium while others were obtained from professional collectors who have the international permits to export limited numbers of these species. By doing what comes naturally, the frogs help Shedd’s sustainability goals.
“By breeding these frogs at Shedd, we can show our guests a bit of the amazing biodiversity of this island in the Indo-Pacific biogeographical region without putting additional pressure on wild mantella populations,” Stacy says. He has had impressive success with these fecund frogs and shares the offspring with other aquariums and zoos.
Stacy started at Shedd in 1997, during the wildly popular “Frogs!” special exhibit. “That’s when I got hooked on them,” he says. Now he’s in charge of the Islands and Lakes gallery, which includes four frog habitats, one of which showcases eight species of the mini multicolored mantellas. Red icons next to six species IDs indicate that those frogs are ranked as endangered or critically endangered by the International Union for Conservation of Nature (IUCN), the oldest and largest global environmental organization and the authority on the status of the world’s plant and animal species.
(Mantellas should not be confused with South America’s poison dart frogs, which you can see in a neighboring habitat. Although both groups are tiny, brightly tinted and toxic, they are unrelated.)
Stacy began breeding frogs as a hobby, and he brought that expertise to the mantellas at Shedd, setting up a climate-controlled room behind the scenes where he could adjust temperature, humidity and light levels to create the seasonal changes that put the amphibians in an amorous mood.
When timed lights make the “days” get longer and Stacy uses a misting bottle to create a light “rain,” the males stake out their territories and start chirping their love songs to lure females to a rendezvous under moss or low-growing plants. Soon the females are so plump with eggs “that you can see through their skin,” Stacy says. The females lay clutches of as many as 70 eggs on the moss or the underside of leaves.
Developing on the ground in the wild, the larvae would be flushed by rain into swamps or ephemeral rainy season ponds, where they’d morph into tadpoles and then adults. At Shedd, Stacy is the moving force, grouping the tadpoles in a series of small containers of water by developmental stage: from fishlike with a yolk sac, gills and big tail, to a halfway stage with back legs and a tail, to the phase where they are four-legged froglets that can graduate from water to moist moss.
Stacy notes that he can have every stage of growth represented in one clutch because the tadpoles develop at staggered rates—a survival strategy akin to not putting all your eggs in one basket. In this case, the frogs aren’t all jumping out of the basket—and, perhaps, into some predator’s mouth—at the same time.
While Shedd’s mantellas are thriving, their counterparts in the wild are not. In fact, frogs are in trouble around the world due to habitat destruction, toxic pollutants, rising temperatures and a lethal disease that is wiping out amphibian populations everywhere.
You can do your part to save our local frogs with these tips from the Association of Zoos and Aquariums, the professional organization that accredits Shedd:
1. Learn about frogs. The Great Lakes region is rich is frog species—and right now you can hear them doing their spring singing in your local forest preserve.
2. Visit Shedd to meet all our frogs and toads.
3. If you’ve got a backyard, create a frog-friendly environment with a pond and planted hiding places. A resident frog will reward you by eating lots of insects, including mosquitoes.
4. Prevent pollution. Please don’t use pesticides and herbicides in your yard. Through runoff, they can contaminate aquatic ecosystems. Frogs absorb chemicals through their semipermeable skin.
5. Conserve water. Remember, it’s coming from an aquatic habitat.
6. Reduce your use of fossil fuels. Amphibians like it cool, so let’s work to slow the rate of climate change.
7. Support Shedd’s restoration of Great Lakes habitats.
Now that you know what we all can do to help save frogs, hop to it!
—Karen Furnweger, web editor