Brown Moor Frogs Turn Blue During Mating Season

The moor frog certainly cannot turn into a prince with true love’s kiss. But this seemingly uninteresting amphibian is capable of something quite spectacular – it changes color from a boring brown to an azure blue, just to be able to distinguish between genders during mating season. The ‘before’ and ‘after’ pictures are really quite unbelievable – it looks they’re two different frogs.

A fully grown adult male moor frog is up to seven centimeters long and reddish-brown in color. But every year, between March and June, the frog exhibits chameleon-like tendencies. During this period, the frogs emerge from their winter hibernation and are naturally in the mood to procreate. They populate the ponds in the lowlands of Central and Southern Europe, completely filling the air with their mating calls. The sounds they create are similar to the noise of air released from a bottle under water.


Photo: Wikimedia Commons

There is an obvious lack of dimorphism in this species – both male and female frogs look pretty much the same. So, as thousands of moor frogs gather at the ponds, it becomes quite difficult for them to differentiate between the sexes. And nature has a perfect answer to this dilemma – the males magically transform their bodies to an attractive shade of blue.


Photo: Billy Linblom

But the male moor frogs aren’t trying to attract females; in fact the brown females do not actively pursue potential mates. It is the male frogs that are always on the look out for a partner, and choosing the wrong partner means wasting valuable time. Moor frogs can be found in great numbers at the Milicz group of ponds in south-western Poland’s Barycz River Valley. The frogspawn in the region get so thick that the waters of the ponds actually look muddy.


Photo: Wikimedia Commons

The males arrive at the shallowest ends of the ponds before the females. They turn blue for just a week and let out their mating calls, waiting for their partners to arrive. When the females finally decide to make an appearance, the males move around a lot, eager to find their potential mates. When a suitable female is spotted, they rush towards her all at once. In all the confusion, it’s actually quite easy to make a mistake. But despite all the color change, the males do end up choosing the wrong partner at times!


Photo: Wikimedia Commons

Source: Ark in Space

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