The fully-grown spring peeper below, sitting on a hydrangea leaf, is 25mm long. It is nowhere near being the smallest frog in the world, which is Paedophryne amanuensis, which at 8 mm long is only about 1/3 of the size of this peeper..
Here it is closer up, with a centimeter measure to show you its size, about 2.5cm.
And even closer
Its Latin name Pseudacris crucifer comes from the cross-shaped marking on its back, rather broken up on this particular individual. Its tiny fingers are translucent, and large toe pads help it grip while climbing.
It is a tree frog, but goes to the water to breed in the spring. It has a deafeningly loud chorus, amplified by a large throat pouch, which makes sleeping in our guest bedroom overlooking the pond quite difficult.
They are insectivores, though this one seems rather intimidated by this amorous pair of large Ambush Bugs.
In the winter they hibernate under tree bark or leaf mould, and can tolerate the freezing of their body fluids down to -8C. I’m not quite sure how they survive a Maine winter, since it routinely goes well below that!