All Creatures Great and Small


As pollution, habitat loss, global warming, and disease increase the number of threatened and endangered species, attempts to protect them are more crucial than ever. That’s where the Frozen Zoo comes in.


By Alisa Opar



Illustration by Bill Mayer

Scientists are racing to determine the origin of the fungus and what makes it lethal to some frogs. But for now, the only line of defense is to bring infected frogs into captivity, treat them, and establish healthy captive colonies with the hopes of returning them to the wild. “The captive program assures that genetic diversity of these frogs is maintained despite declines and extinctions in the wild,” says Pessier. “It is an emergency measure, but necessary, since the frogs are disappearing so quickly.” Having cells from the skin of these frogs stored at the Frozen Zoo could enhance these measures dramatically, he says. By studying cell lines, researchers may be able to better understand how the fungus kills amphibians and determine ways to combat it.

The biggest challenge right now is growing the cells properly. The samples stored at the Frozen Zoo must be uncontaminated—that is, free of chemicals, fungi, and other contaminants that interfere with research and testing procedures. While a simple cleaning process to take a skin sample usually suffices, the moist, porous skin of frogs is an ecosystem unto itself; it hosts anti-fungal bacteria and other microorganisms, which makes getting a proper sample difficult. So researchers are working on methods for obtaining viable samples from adult amphibians that have died naturally—perhaps

taking cells from inside their eyes. To date, they’ve grown cells from two species, American bullfrogs and African claw-toed frogs.

They hope studying these samples can lead to clues that will help them protect at-risk species.

It’s a start, but Ryder stresses that collecting a reserve of amphibian cells will require cooperation from scientists and governments around the world. To that end, Frozen Zoo researchers have begun working with a variety of conservation groups, some of which are bringing amphibians into captivity to protect them from the lethal fungus. Such efforts, explains Ryder as he gently places a rack of cylinders back into the freezer, are crucial for saving all species, not just amphibians. “Our job right now is to fill as many of these freezers as we can and to get as many other people to do the same and to protect it as a resource for the future,” says Ryder. That way, scientists may have the same success with other species as they’ve had with condors. “We’re still at the very early stages of learning how to employ the Frozen Zoo and being able to extract information from it. Who knows what we’ll be able to do in the future?”

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Issue 25



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