Frog

A frog is a tailless amphibian that lives on land and in water. The wood frog of North America spends the winter frozen solid. Ice forms around its organs, its heart stops beating and it stops breathing. In spring it thaws out, its heart starts again and it hops off.^[1] It is the only animal that treats winter the way people treat leftovers.

How it freezes

As the frog starts to freeze, its liver floods its body with sugar, which acts as an antifreeze inside its cells and stops them being damaged by ice. Up to around two-thirds of the water in its body can freeze.^[2] The frog does not choose the date; it waits for the weather to do it.

Other habits

Frogs do not usually drink with their mouths. They absorb water through their skin, often from a special patch on their bellies called a drinking patch. A frog sitting in a puddle is having a drink.

Many frogs use their eyes to help them swallow. When a frog swallows, it pulls its large eyeballs down into its head, where they press on the food and help push it down the throat. A frog blinking at its dinner is, therefore, eating it.

• Drinks with: its skin.
• Swallows with: its eyes, partly.
• Spends the winter: frozen.

See also

• Ice – which it can survive
• Puddle – a drink
• List of things that are cold – where it goes in winter
• Axolotl – an amphibian that never grew up

References

1. Thaw, T. (1990). Back in the Spring. Pond Press.
2. Glucose, G. (2001). “Sugar as Antifreeze”. Cold Biology 2: 3.
3. Gulp, G. (2006). “Eyes, Used for Eating”. Amphibian Digest 1: 1.