Image Credit: NGUYEN Hao Quang

This lovely milky frog will someday learn to fly

  • November 13, 2017

It might look like something you’d buy at your local corner store, but this adorable frog has got something far more interesting going on than looking like a perfectly made piece of chocolate.

Contributor
Bec Crew

Becky Crew is a Sydney-based science communicator with a love for weird and wonderful animals. From strange behaviours and special adaptations to newly discovered species and the researchers who find them, her topics celebrate how alien yet relatable so many of the creatures that live amongst us can be.

THIS IS THE Annam flying frog (Rhacophorus annamensis), a rare and hefty frog that lives in the lofty forest canopies of South East Asia, and uses specialised skin flaps between its toes to fly from tree to tree.

This particular frog is a juvenile - when Annam flying frogs are young, they take on a creamy white appearance, with rich brown Dalmatian-like splotches all over.

But as they grow older, they lose this colouration altogether, and will either transition to light grey with speckles, or brown or dark red all over, which isn't quite so delicious.

You can’t tell from the pictures, but these frogs are bigger than you’d expect.

The females are typically larger than the males, and can grow to be an impressive 10 cm long, which makes them slightly smaller than the length of an iPhone 6.

That’s nowhere near the ginormous Goliath frog (Conraua goliath), which stretches to more than 30 cm, but it’s still far heftier than your average tree frog.

Native to the Annamite Mountains in Cambodia and Vietnam, the Annam flying frog has evolved a very efficient method for skipping through the treetops - flying.

Well, when we say flying, we really mean gliding, because flying needs to be powered by something like regular wing movements or a motor, whereas gliding is more like… falling with style.

There are three frog genera that have evolved feet large and fleshy enough to let them soar through the air: Ecnomiohyla, the marvellous frogs; Polypedates, the whipping frogs; and Rhacophorus, which don’t have a collective common name to speak of, but they were the first ever frogs to have their gliding abilities documented.

One of the Annam flying frog’s very close relatives, Wallace’s flying frog (Rhacophorus nigropalmatus), was first discovered in 1855 by British naturalist Alfred Russel Wallace, and it was like nothing scientists had seen before.

Its hands and feet are literally as big as its head, and this allows it to glide as far as it is high - for example, it can glide for 15 metres if its starting point is 15 metres above the ground.

Here’s Bill Bailey showing off an extremely calm Wallace’s flying frog:

The existence of a frog like Wallace’s, which had grown beyond leaping and into something far more effective, helped Charles Darwin form the beginnings of his theory of evolution by natural selection in the mid 19th century.

Poor Wallace was already in the process of formulating his own very similar theory, but threw in the towel once Darwin published On the Origin of Species in 1859.

I guess if you’re going to be scooped, it might as well be by Charles Darwin himself.

Here’s more footage of flying frogs (and lizards!) doing their thing:

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