Cuba’s wildlife is varied and unlike wildlife anywhere else in the world. This is no coincidence – the island, while close to its North and South American neighbors, has been evolving in isolation for thousands of years. Extraordinary things tend to happen to species evolving in isolation; the unique combination of predators and competition for resources – or, often times, the lack thereof – allows species to adapt in ways they never would on the mainland. Species adopt new characteristics, behaviors, or patterns that distinguish them from their mainland counterparts.
In some cases, island species move in the direction of gigantism, as the lack of competition and predators allows them to use all available resources and grow as large as possible. In other cases, such as in Cuba, species will tend toward dwarfism, becoming smaller and conserving resources. Dwarfism has its advantages, as it enables organisms to absorb nutrients and energy more efficiently, hide from predators more easily, and ably cope with stressful environmental conditions. This drastic evolutionary size change in species is known as Foster’s rule, or the island rule (as the phenomenon is a core principle of island biogeography). Furthermore, the size change in species can happen very quickly on islands, much more quickly than evolutionary changes in mainland species. Mutations and adaptions spread through generations rapidly since there is a much smaller gene pool in the isolated island environment.
Thanks to the special evolution that has taken place on Cuba, the island is now home to some of the smallest and most interesting species on Earth. The bee hummingbird, known locally as the zuzuncito, is the smallest bird in the world – named because it is no bigger than a honeybee! This tiny bird is often mistaken for an insect, and is thus prey for larger birds, frogs, fish, and tropical spiders. Cuba is also home to the second smallest frog in the world, the Mount Iberia Eleuth. This miniscule frog, only half the size of a dime, lives in two relatively small regions of the country and requires a great deal of humidity to survive. Other dwarfed species endemic to Cuba include the world’s smallest scorpion, one of the world’s smallest owls, and extremely small varieties of bats.
The unusual evolutionary trends of Cuba extend not only to dwarfed species, but to animals with other unique characteristics. Perhaps the greatest example of this are the polymitas, or Cuba’s painted snails. These snails are known for their vibrantly colored shells, which come in a variety of dazzling hues and, of course, are found nowhere else in the world.
Unfortunately, several of Cuba’s distinctive endemic species are becoming or are already threatened. This is due to a variety of factors, many of them caused by human activity: habitat loss, deforestation, agricultural development and mining, and tourism. The polymitas are also “hunted” for their shells, popular as jewelry and as collectors’ items, which seriously threatens their populations. As Cuba continues to open its doors to the world, its great diversity of plant, reptile, bird, and mammal species will be further threatened by human interference.
NARRATOR: Cuba is the giant of the Caribbean. With nearly half of the region’s landmass, the sprawling island was forged using nearly every trick in nature’s book… wet, tropical forests meet pine-cloaked mountains… and sultry wetlands give way to dry, desert coasts. But despite the island’s impressive grandeur, much of Cuba’s natural splendor plays out on a decidedly smaller stage…
Cuba is home to the world’s smallest bat, one of the smallest owls, and the smallest bird of all… a hummingbird that weighs less than a penny. The bee hummingbird is a miracle of evolution… a descendant of the dinosaurs barely two inches tall. From their treetop lookouts, they perform acrobatic aerial displays, scouting for the best blossoms to satisfy their outsized appetites. In a single day, they’ll eat half their bodyweight… in nectar and insects. The bird’s size does have its disadvantages… when competing for food, its bigger neighbor, the Cuban emerald, insists on first pick.
One of the tiniest of Cuba’s creatures lives not in the trees but on the forest floor – a frog barely half the size of its own name… Eleutherodactylus Iberia (eh-lou-thero-dack-tah-less Eee-berry-ah), the smallest frog in the northern hemisphere. Life among the leaf litter is full of constant danger… and this bite-sized frog knows he can be a tempting treat for hungry neighbors… …but not today.
Making their way down from their treetop shelters, some of the forest’s gaudiest creatures are also on the hunt. These are Cuba’s famous “painted snails,” the polymita (pah-leh-meet-ah). With eyes perched on long stalks, the polymita seek out water and lichen on the leaves of ferns and other plants. Today, something else has caught this snail’s eye…an attractive mate. Like most snails, polymita are hermaphrodites (her-maff-rah-dites), both male and female, which means anyone is a possible partner.
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