A little but mighty frog called 'Coqui'.

The Coqui has been a cultural symbol of Puerto Rico history for centuries. Since the time of our native Taino inhabitants and its presence shown on many stone engravings. The species is named 'Co-qui', for the loud call the males make at night, calling the females and keeping other males coquies away. There are about 17 species of coqui.
They belong to the Eleutherodactylidae family, which in Greek means "tree frog". This genera has no interdigital membrane, which could indicate that they are not adapted to swim. The smallest coqui is around 1 to 2 inches long, females are bigger than males coquies. Like many amphibians they prefer humid habitats and are more active at night, when you can hear their beautiful and loud melodies.

Rather than passing through a free living larva (tadpole) stage, which means the parents don't have to lay their eggs on the water, as other amphibians do, after the egg cracks open a tiny but fully functional coqui emerges. Males guard the eggs for about 30 days, until the little coquies are born.

If you visit the Island of Puerto Rico, don't be surprised that at soon as the sun hides behind the mountains, the night comes alive dancing along an orchestra directed by thousands of Coquies. ;)