Coqui frog

"Full-grown male coquís measure, from snout to vent, from 30 to 37 mm, with an average of 34 mm, while full-grown females measure from 36 to 52 mm, with an average of 41 mm. The size differences between genders are a result of additional energy consumption related to breeding behavior by males.[5]

Contrary to popular belief and artistic renditions, which depict the species as green, coquís commonly have a gray or gray-brown coloration. Unlike many frogs, coquís do not possess swimming membranes between their digits, so are not adapted to swim. However, like all tree frogs, they possess small pads on the tips of their toes which help them adhere to moistened or slippery surfaces." -- Wikipedia