Frog populations are plummeting all around the world, with many species facing extinction. Battling extensive habitat loss and the killer chytrid fungus, scientists are attempting to save some species through captive breeding programs. Their attempts to use techniques borrowed from human infertility clinics to help frogs mate highlights just how specialized amphibian reproduction truly is: From courtship to egg fertilization, distinct frog types seem to do each step a bit differently. The frog fertility clinic is not a “one species fits all” kind of place, explains Pierre Comizzoli from the Smithsonian Conservation Biology Institute in this short video.

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Video Transcript:

Assisted reproduction in frogs

Eliene Augenbraun: “Frog populations are plummeting all around the world due to habitat loss and attack by the chytrid fungus, so scientists are using techniques borrowed from human infertility clinics to help them mate in captivity. All frogs reproduce using the same basic steps. Males produce sperm, females lay eggs. When the sperm fertilizes an egg, a baby frog — a tadpole — starts to form. The tadpole hatches, grows and transforms into a frog, but every type of frog does each step a little differently based on its ecological niche, so the frog assisted reproduction clinic is not a one-species-fits-all kind of place. Pierre Comizzoli from the Smithsonian Conservation Biology Institute helps endangered species.”

Pierre Comizzoli: “What has been developed in assisted reproduction for humans is absolutely amazing. Honestly, in the animal world, we are far from being able to replicate what’s been done in humans, and I can tell you that in amphibians it’s even more challenging.”

Eliene Augenbraun: “The Panamanian golden frog is a national symbol in Panama, but they’ve not been seen in the wild since 2009. Comizzoli applied mammalian techniques to preserving this amphibian. One breeding colony is at the Maryland Zoo. Kevin Barrett is their reptile and amphibian conservation manager. But to the roughly 2,000 Panamanian golden frogs living in American zoos, he’s much, much more.”

Kevin Barrett: “I’m also involved as the stud book keeper for the frogs, so that means I actually keep tabs on all the frogs in North America.”

Eliene Augenbraun: “… making sure to maintain genetic diversity in the population. The Maryland Zoo set up special breeding tanks with rushing waterfalls to make the golden frog feel at home and in the mood. Part of their mating ritual is for males to wave. Let’s play it again so you can catch that. Males and females are not always ready and available to mate at the same time and in the same place. Frog eggs cannot be frozen, so labs focus on freezing sperm but…”

Pierre Comizzoli: “The first position is going to be outside of the body so if the sperm really survives only a couple of minutes compared to, you know, the several hours for the sperm collected from a mammal.”

Eliene Augenbraun: “It can take many experiments to figure out how to collect, freeze, store and reanimate sperm so they’re viable, and then conditions need to be just right for fertilization.”

Pierre Comizzoli: “Whenever you’re thinking of assisted reproduction, the way you handle the semen samples, the way you freeze them, everything is going to be different from one species to the other.”

Eliene Augenbraun: “Are there any generalizations you can make about assisted animal reproduction?”

Pierre Comizzoli: “It’s absolutely nuts.”

Eliene Augenbraun: “Zoos around the world are trying to keep endangered species alive and breeding. Hopefully, when their habitats are restored, at least a few species of frogs will be ready to move out of the lab and back into the forest. For Knowable Magazine, I’m Eliene Augenbraun.”