How can a frog crawl up a window pane?

Ordinary frogs that croak in the grass and dive into the pond^ cannot walk up window panes, But they have shy little cousins who live in the woods and these fellows are born climbers. They can crawl up the straight side of a tree trunk, cling to a swaying bough   and they can even crawl up the shiny face of a window pane.

These froggy acrobats are the tree frogs. Their dainty little toes are tipped with round pads that act as suckers. Tree frogs can climb up and down and around impossible places because the grippers on their feet are strong enough to hold the weight of their small bodies,