The common coqui frog, or Eleutherodactylus coqui, is the unofficial, but culturally accepted, symbol of Puerto Rico. The frog's common name comes from the loud "ko-kee" sound that the male of species make at night. Because the distinctive nighttime sounds are heard throughout most of the evening in Puerto Rico, the frog has become representative of the island's cultural heritage.
The coqui frog is one of the smallest frog species found worldwide. Females are slightly larger than males and average about 1.6 inches in length. The loud and high-pitched "ko-kee" sounds produced by the males serve a dual purpose. The "ko" sound establishes a frog's territorial boundary and the "kee" sound is a mating call.
The coqui frog's symbolic representation of the island of Puerto Rico can be seen in tourist items, murals and tattoos. The coqui frog can also be found in Hawaii, but their large population has caused them to become an invasive species in the region.