Tim Low lives in a state of perpetual surprise at everything wild and alive. His response is to write searching books, Australian Geographic articles and this blog. His book Where Song Began (Penguin, 2014) recently became the first nature book ever to win the Australian Book Industry Award for best general non-fiction. Tim's newest book is called The New Nature.
FROGS ARE SUPPOSED to croak, but here in Australia they don’t seem to know that. Around a busy pond at night when males are wooing partners every kind of sound is thrown around.
The common names of our frogs say it all. Australia has the moaning frog, wailing frog, stuttering frog, humming frog, chattering rock frog and laughing tree frog.
It has some that recall artisans at work: the woodworker frog, shoemaker frog, stonemason toadlet and tinker frog. All of their calls sound like hard objects being struck in a workshop.
Adding to the variety are the barking frog, bleating tree frog and growling grass frog, plus the buzzing frog, beeping froglet, clicking froglet and whirring tree frog.
We were taught as youngsters that dogs bark, sheep bleat and frogs croak. Britain only has two frog species, and one is so rare that children’s books coming out of England are entitled to speak of one frog sound – the croak of the European common frog (Rana temporaria).
By a lucky coincidence ‘croak’ works in Australia, because it suits our most popular frog, the green tree frog (Litoria caerulea). These sound nothing like the original croakers from Europe, but when males advertise from drainpipes on hot rainy nights ‘croak croak croak’ is a good rendition.
A green tree frog. (Image Credit: Matt/Wikimedia)
Australia abounds in frogs, with more than 230 species, and each needs its own call to avoid mix-ups at ponds, where half a dozen species may seek mates on the same night. When females take a partner for the evening it is not how he looks that counts but how he sounds. If everyone croaked there would be many mixed matings, with bad outcomes for all.
Calls are so pivotal to frogs that evolution has produced species that we can’t identify except with our ears. Biologist Conrad Hoskin named the Kuranda tree frog (Litoria myola) and it was the ‘distinctive short, fast tapping call’ that he nominated as the only feature (other than genes) to separate it from the identical-looking green-eyed tree frog (Litoria genimaculata).
Frogs invite us to use our ears more when we are outdoors. I’m not so keen on the motorbike frog (Litoria moorei), which sounds like a bike roaring round a racetrack, gear changes included, but I really enjoy it when the banjo frogs (Limnodynastes species) are performing.