GREEN tree frogs never get parched in Australia’s dry season; they just supply their own water.

Chris Tracy at Charles Darwin University in Darwin wondered why Litoria caerulea ventured out of the tree hollows they hide in into the cool night air. “Frogs usually become sluggish when the temperature drops,” he says.

His team found that when the frogs returned to the humid hollows they became 0.2 grams heavier. By cooling down outside, the frogs forced moisture in the hollows’ air to condense on their skin, of which they could drink 60 per cent (American Naturalist, in press).

This water boost “could mean the difference between surviving the dry season or not”, says Tracy.

When this article was first posted, the first sentence referred to “summer”, and Chris Tracy’s name was spelled incorrectly.