Tuesday, January 13, 2009

Didja Hear the One About the Frogs?

Great story about frogs in the Austalian news. One of the great biological crises of recent times is the ongoing demise of whole species of frogs. For years, it's been argued that this crisis stems from climate change, and has been used as yet another reason to change our ways regarding carbon emission. As the frogs go, so goes the planet.

Recently, though, it's been discovered that it's a fungus and not climate change that is responsible for frogs' mass extinction. The chytrid fungus attacks the skin of frogs, making it difficult for the frogs to breathe. (8th grade biology flashback: frogs breathe through their skin.) It's treatable (using the same basic antibiotic we use for pink eye, actually), but in some cases it's already too late. In Australia alone six species of frog have been wiped out.

Now, the fungus travels in waves, like a virus. So you can see how it could easily spread all the way across Europe and Asia and down into Africa, and also between the Americas. But how did it get to Australia?

The answer is actually a very unusual version of a classic Australian problem. Soon after Brits arrived in Australia, they began to introduce all sorts of flora and fauna from Europe into their new home. And in many cases, the country was not equipped to handle the new species, and things got out of hand. The classic case, which I've mentioned before, is the rabbit. Australia has no natural land predators, other than the dingo (a sort of wild dog); consequently, there was nothing to keep the rabbit population from exploding. Which it did, in the process devouring lots of native plant life that didn't grow back in the way one might anticipate in parts of Europe.

Similar problems have arisen from the introduction of some species of plants, bugs, including, we now know, a frog. In the 1930s, African frogs were exported not only to Australia but all over the world. You won't believe me, but it's true -- they were used as a pregnancy test.

I think it's fair to say the test worked a little different back then. Apparently pregnant women secrete certain hormones that cause female African frogs to ovulate. Which caused a variation on the popular saying about the fat lady singing: "I'm not pregnant til the African frog ovulates."


The African frog carries the chytrid fungus without getting sick from it. Its introduction into the Australian ecosystem brought with it this fungus. And so the situation we have today.

There's some sort of joke to be made here; I'm gonna let you fill in the blank.

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