Fact sheet
Puerto Rico - U.S.A.

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El Yunque was originally set aside in 1876 by the Spanish Crown and is one of the oldest reserves in the Western Hemisphere


El Yunque Fact Sheet

How much does it rain in the rain forest?
That depends on which part of the forest you are in. Generally speaking, the higher you are in the forest, the more it will rain. Maximum amounts occurring at the forest’s highest elevations have reached over 250 inches (635 centimeters) annually, while lower elevations receive only 50-60 inches (120-150 centimeters).

Where does all the water come from?
It comes from rainfall much of which is brought to us by the Trade Winds. The Trade Winds, with their moisture laden air sweep eastward across the Atlantic ocean and Caribbean sea from Africa. These constant wind currents were named the Trade Winds because they filled the sails of ships sailing from Europe and Africa that carried trade goods to and from the new world. When the Trade Wind clouds reach mountain ranges like those in the Caribbean National Forest, they are driven upward along the slopes. As the moisture laden air rises it becomes colder and condenses into raindrops which fall on the forest below. This phenomenon is known as “orographic” rainfall and it produces much of the rain the forest receives each year. It is estimated that the forest’s average rainfall (120 inches-304 centimeters/year) would yield 160 billion gallons (605 billion liters) annually, enough to supply the municipality of San Juan with a population of half a million people for over two years!

Are there any snakes in the Caribbean National Forest?
Yes, there are 5 or 6 species of snakes that live in the forest. They are rarely seen, are non-poisonous and pose no threat to humans. The largest of these is the Puerto Rican Boa which can reach a length of 6 feet. It is a tree climbing predator, hunting at night for small animals and bird eggs. It can sometimes be seen at lower elevations coiled-up and sleeping during the day. The other snake species found in the forest are much smaller and do not climb trees and so are much harder to find.

Is there any gold left in the rivers of the Caribbean National Forest?
Yes, but don’t expect to become wealthy by searching for it; estimates vary, but at most you could expect to collect no more than US$2.00 worth for a full day’s hard work! In the early days gold was removed from the sands of rivers such as the Río Mameyes which parallels PR 191 on the way to the Caribbean National Forest, but the source of the gold was never discovered and the work was eventually discontinued.

Why are there no large animals in the Caribbean National Forest?
The island of Puerto Rico was formed by volcanic activity during the Triassic period. Thrusting out of the Caribbean sea it had no land bridge to any continent. Consequently, the animals of Puerto Rico (and the Caribbean National Forest) originally arrived on the island by either swimming, floating or flying, and thus were smaller in size than those found on large continents. The largest mammalian animals in the forest are the rats, bats and the mongoose. A reptile, the Puerto Rican Boa can grow to a length of 6 feet but poses no threat to humans. None of the animals of the forest, large or small (including insects) are poisonous. The tarantulas, scorpions and centipedes found in the forest can provide a venomous bite (similar to a bee sting) but are only dangerous to those who are allergic!

I have heard that it “rains frogs” in the Caribbean National Forest. Is this true?
This interesting forest legend involving Puerto Rico’s indigenous and beloved Coquí frog Eleutherodactylus coquí is actually based on scientific fact! During those times of the year when the humidity is high, the tiny Coquí frogs will climb to the forest canopy, sometimes as high as 100 feet (30 meters). Predators such as the Tarantula anticipating this behavior, lay in wait for the frogs. Many frogs are caught by the predators during their ascent. Instead of returning to the ground by the same dangerous path, the surviving frogs prefer to launch themselves into the air, thus bypassing their predators on the way down. The tiny frogs are almost weightless so that they float to the forest floor unharmed. If you are lucky enough to be sitting under a tree when this is happening, you will indeed be “rained upon” by tiny frogs!

Why is the Puerto Rican Parrot almost extinct?
The Puerto Rican Parrot Amazona vittata is the only native parrot on the island. When Christopher Columbus arrived here on his second voyage of exploration in 1493, these birds were a common sight throughout the island. This parrot is a forest bird which requires large hollow tree trunks for nesting. As trees were cut-down by the original settlers to make way for farms, the parrots gradually retreated into the remaining patches of forest. During the ensuing centuries it is estimated that 85% of the island was deforested. Only in the protected Caribbean National Forest could the parrots still find the large trees that they needed for nesting. Until laws were enforced that stopped parrot hunting in the forest the parrot population decreased substantially. In 1968 the Puerto Rican Parrot was placed on the Federal Endangered Species List and cooperative effort by the USDA Forest Service, the US Fish and Wildlife Service, the Commonwealth of Puerto Rico Department of Natural and Environmental Resources and the World Wildlife Fund were begun to recover this important species. The continuing decline in the parrot population is results from a number of factors; nest competition by the Pearly-eyed Thrasher, an aggressive bird that has invaded the parrot’s prime habitat; an infusion of honeybees that have taken over cavities in many of the Palo Colorado trees suitable for parrot nesting, and for various other reasons.

A parrot aviary has been established in the Caribbean National Forest. Here parrot eggs are hatched and fledged in captivity, birds are prepared for living in the wild and subsequently released. The present population in the wild numbers less than 50 individual birds but captive individuals and pairs are being released into the wild on a yearly basis, and their survival rates are encouraging.


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Collaborating Illustrator: Jorge Luis Rodríguez; Bronx, NY