Moor Frog: a two-minute wildlife lesson

Frogs and Toads · day 3 of 7

Five facts

1. For just a few days each spring, at the peak of the breeding season, male moor frogs turn bright blue. Females stay brown.
2. The blue we see is only part of the show. The biggest colour change happens in ultraviolet light, which human eyes cannot see.
3. Moor frogs can freeze and survive. Frogs from Siberia and European Russia have come through freezing as cold as -16 °C.
4. In spring, males sing together in groups. Their chorus sounds a bit like air bubbling out of an empty bottle held underwater.
5. Rana arvalis, its scientific name, translates as frog of the fields. Another name for it is the Altai brown frog.

The quiz

1. What colour do male moor frogs turn for a few days in spring?

• Bright red
• Bright blue (correct)
• Pure white
• Bright yellow

At the peak of the breeding season, males turn blue while females stay brown.

2. Where does the biggest colour change of the males happen?

• Only on their tongue
• In infrared light
• In ultraviolet light, invisible to us (correct)
• Only inside their eyes

The greatest change is in ultraviolet light, which human eyes cannot see.

3. How cold a freeze can moor frogs from Siberia and European Russia survive?

• -16 °C (correct)
• -60 °C
• -100 °C
• They die at the first frost

These frogs can survive freezing as cold as -16 °C.

4. What does a chorus of male moor frogs sound like?

• A dog barking
• A bird whistling
• A bell ringing
• Air escaping from a bottle underwater (correct)

Their chorus sounds like air escaping from an empty bottle held underwater.

5. What does the scientific name Rana arvalis mean?

• Frog of the mountains
• Frog of the rivers
• Frog of the fields (correct)
• Blue frog

Rana arvalis means frog of the fields.

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