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122 IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 BONNER

KINGS PLAY CHESS ON FANCY GLASS STOOLS

Anyone know that sentence? It’s a mnemonic device, a short-
hand way of remembering the categories scientists use to classify
all life on Earth. The first letters of each word are the keys:

KINGDOM, PHYLUM, CLASS, ORDER, FAMILY,
GENUS, and SPECIES

Now, if I said that half of an entire kingdom was going to
become extinct in the next five years — say, the Animal

Kingdom — there would be widespread global panic. Little
wonder, as it would be the end of life on this planet as we know
it. On the other hand, if I told you that we just lost another
species, you might shrug your shoulders. You might figure that

losing a single species is a little like popping a rivet on an air-
plane. Planes have oodles of rivets. You wouldn’t want to lose too
many, and you wouldn’t want to lose an important one — like
the last rivet holding the wing on. But losing an occasional rivet
isn’t exactly catastrophic.

Where we have problems is toward the middle of our cat-
egories. For example, what if we only lose half a “Class” of ani-
mals? A Class isn’t as broadly encompassing as a Kingdom or a
Phylum, but it takes in a lot more than a species or a Genus. Is
losing half a Class a catastrophe, or is it just another popped
rivet?

C O M M E N T A R Y

What Do We Lose If We Lose the Frogs?1

Jeffrey P. Bonner

President, Saint Louis Zoo
St. Louis, Missouri 63110

The Fire Salamander (Salamandra salamandra) is IUCN-Red-listed as being of “Least Concern” in view of its wide distribution, tolerance of a
degree of habitat modification, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more
threatened category. However, even such species need to be monitored carefully, as changes in status can occur rapidly.

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1 Reprinted with permission of the St. Louis Post-Dispatch, copyright
2006.



Well, we’re about to find out. In the next five to ten years,
about half of the different kinds of animals that make up the
Class known as amphibians probably will become extinct. There
are about 6,000 known species in the class of amphibians: frogs,
toads, and salamanders take in most of them. As I write this, 32
percent of those 6,000 are threatened, and another 23 percent
are believed to be threatened (we don’t have quite enough data
to make the call with absolute certainty).

Amphibians face many of the same problems that other
threatened species face: Habitat loss, climate change, pollution,
and so on. But they also face a unique challenge. There is a fun-
gus, which was born in Africa, that is sweeping our planet. It’s
called the chytrid fungus, and wherever it arrives, it kills about
80 percent of the amphibians in the area within a year. It is lethal
only at certain altitudes, so it won’t destroy all of the world’s
amphibians, but more than half is a pretty conservative estimate.

Scientists working with the St. Louis Zoo just confirmed
that it’s here in Missouri. The fungus cannot be stopped in the
wild. Our only hope is to get to the amphibians before the fun-
gus arrives and bring them into zoos and aquariums for breed-
ing and safe-keeping. The hope is that the fungus subsequently
will run its course, after which the animals can be released again.
Call it “protective custody.”

We do not know what the assault of the chytrid fungus
means for the web of life that sustains us. Frogs and their kin are
both predators and prey. They are critically important in sustain-
ing the delicate balance of nature. But are they just another rivet
or do they keep the wings on the plane? The skin of amphibians
is more permeable than ours — things pass through it fairly eas-
ily — so they have developed some unique biological strategies
to protect themselves. For example, their skin produces a wide
variety of substances that kill microbes and viruses.

IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 123COMMENTARY

The Southern Bell Frog (Litoria raniformis) is endangered in Australia
and listed as such on the IUCN Red List. However, introduced pop-
ulations in New Zealand currently are doing well — but may be sus-
ceptible to the chytrid fungus, which has been documented in New
Zealand during the past decade.

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The Maud Island Frog (Leiopelma pakeka) is endangered in New Zealand and listed as “vulnerable” on the IUCN Red List.

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124 IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007

Last year, 14 of these substances, taken from just a handful
of different frog species, were tested in a lab; three of the 14
showed a remarkable capacity to completely inhibit HIV infec-
tions. I was surprised that a discovery that shows such promise
for inhibiting the mucosal transmission of AIDS didn’t make the
news, but maybe I shouldn’t be: The fact that we’re going to have
some very silent nights on this planet in just a few short years
hasn’t attracted much attention, either.

Contemplating the silence that will replace the thunderous
evening chorus of amphibians’ calls is bad enough. Even worse
is that with the loss of those species, we will lose so many cures
for so many things. And it is worse still to imagine what losing
half of the world’s species of amphibians may mean as we strug-
gle to keep our living airplane from disintegrating.

When I studied biology in high school, I had a delightful
mental image of those Kings Playing Chess while sitting On those
Fancy Glass Stools. Now it turns out that we are very much like
those kings: Idling away our time when we should be responding
to a horrible threat to our Kingdom. It is not too late to save many
— perhaps most, maybe even all — of the amphibians. They are
comparatively easy to find and keep healthy in zoos and aquari-
ums until it’s safe to release them back into the wild.

The Saint Louis Zoo, for example, has returned thousands of
Puerto Rican Crested Toad (Bufo lemur) tadpoles to the pools of
their homeland. We also are working in Ecuador to create a survival
center in Quito, and we have teamed up with other zoos to create
a survival center in rural Georgia for amphibians of North America.
And right here, at one of the centers of the zoo’s WildCare Institute,
we are working to save Missouri’s rapidly declining population of
Hellbenders (Cryptobranchus alleganiensis).

In this struggle, time is short, and we need your awareness
and support. Call us at the St. Louis Zoo, and we’ll tell you how
you can help.

BONNER

This juvenile Ozark Hellbender (Cryptobranchus alleganiensis) at the St.
Louis Zoo WildCare Institute is part of an effort to save this species.
Declining populations throughout this “near-threatened” species’ range
are attributable to habitat degradation, predation on eggs and larvae by
exotic species, and agricultural run-off that might interfere with nor-
mal reproduction.

Captive-breeding programs, including that at the St. Louis Zoo, are
working to reestablish the critically endangered Puerto Rican Crested
Toad (Bufo lemur) in its natural habitat.

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