Frog Epidemic Slowly Crystalizing

I have had this nasty image in my mind all morning after reading a recent study about frogs: I am 20 years older and am with my 12-year-old son at the zoo. He says, "Dad, what's with all the different colored frogs? Are they genetically engineered that way?"

I say, "No, son, back when I was a kid, there were hundreds of frog species in North America alone. Not like today, where they are only in zoos."

Like song birds in Racheal Carson's Silent Spring, frogs and salamanders are early indicators of stresses to the environment. Their thin, porous skin and dual life in and out of the water make them vulnerable to chemical and physical changes. And they are not doing well.

Global amphibian populations are plummeting. An estimated third of the 6,000 amphibians in the world may be extinct by 2100; 100 in the next decade alone. The latest killer is a members of a fungus family called chytrids (KIT-rids). Since appearing in the late 90s, these things have been like a Biblical plague. But instead of frogs falling from the skies, frogs have been dying literally in heaps — especially around high alpine lakes, according to a new study.

The study, out this week from the Imperial School of London, suggests that chytrids are at home just about anywhere. In alpine lakes around 6,00 feet, however, they can morph into horrendous epidemics that kill 80- 100 percent of the frogs. This is staggering - on par with sudden oak death of the chestnut blight that killed almost every chestnut on the continent.

Vance Vredenberg, who has studied chytrid frog die-offs in California's Sierra Nevada says the team is "on to something very significant." Currently, we know very little about this disease and scientists are essentially waiting it out and hoping for the best. New studies suggest that if a frog can survive the first wave of die-offs, it might re-establish a new (perhaps inbred) population.

So did humans unleash this on the already-beleaguered frogs of the world? Probably. Very little is known about the disease so far, but it was probably spread by non-native toads that we used in early pregnancy tests. Like many diseases, it may be complicated by climate change or pollution - two things that are already wiping out frogs.

But here's the sad thing about all of this. I remember the din of frogs on a warm summer evening just outside St. Louis. I'll tell my kids about it, but they'll hear it less often. Their kids, maybe not at all. That's the beauty of extinction - the next generation won't know what they are missing. Just ask the bison, the American chestnut, the California grizzly bear and the American jaguar.

Photographer Joel Sartore has more images of endangered amphibians in his new book RARE. To learn more about chytids and hear a few California frogs imperiled by them listen to this.

Photo credit: Joel Sartore Photography