During the 19th century, forests covered about three-fourths of Puerto Rico. Today, however, only one-fourth of the island is forested. Flowering trees still abound, and the butterfly tree, African tulip, and flamboyán (royal poinciana) add bright reds and pinks to Puerto Rico's lush green landscape. Among hardwoods, now rare, are nutmeg, satinwood, Spanish elm, and Spanish cedar. Pre-Columbian peoples cultivated yucca, yams, peanuts, hot peppers, tobacco, and cotton. Pineapple guava, tamarind, and cashews are indigenous, and such fruits as mamey, jobo guanábana, and quenepa are new to most visitors. Coconuts, coffee, sugarcane, plantains, mangoes, and most citrus fruits were introduced by the Spanish.
The only mammal found on the island by the conquistadores was a kind of barkless dog, now extinct. Virtually all present-day mammals have been introduced, including horses, cattle, cats, and dogs. The only troublesome mammal is the mongoose, brought in from India to control reptiles in the cane fields and now wild in remote rural areas. Mosquitoes and sand flies are common pests, but the only dangerous insect is the giant centipede, whose sting is painful but rarely fatal. Perhaps the island's best-known inhabitant is the golden coqui, a tiny tree frog whose call of "ko-kee, ko-kee" is heard all through the night; it is a threatened species. Marine life is extraordinarily abundant, including many tropical fish, crabs, and corals. Puerto Rico has some 200 bird species, many of which live in the rain forest. Thrushes, orioles, grosbeaks, and hummingbirds are common, and the reinita and pitirre are distinctive to the island. Several parrot species are rare, and the Puerto Rican parrot is endangered. Also on the endangered list are the yellow-shouldered blackbird and the Puerto Rican plain pigeon, Puerto Rican whippoorwill, Culebra giant anole, Puerto Rican boa, and Monita gecko. The Mona boa and Mona ground iguana are threatened. There are three national wildlife refuges, covering a total of 2,425 acres (981 hectares).