Meet Eleutherodactylus iberia, one of the many frog species found only in Cuba. Among the world’s smallest known frogs, adults of this species can fit on a human fingernail with room to spare.
This minuscule amphibian is just one Cuban example that might fit the so-called “island rule,” which proposes that over time, animals on islands tend to evolve smaller body sizes when food resources are constrained, or evolve to become bigger when there is less pressure from predators.
Until about 6,000 years ago, Cuba’s forests were home to Ornimegalonyx, the largest owl ever known. Researchers estimate that this awesome bird weighed as much as 38 pounds in life—three times heavier than today’s largest living owls.
Cuba was also home to Megalocnus rodens, a giant ground sloth. While similar giant sloths went extinct about 11,000 years ago in North and South America, radiocarbon dating shows that Megalocnus survived in the forests of Cuba until just a few thousand years ago, long after its counterparts on the mainland were wiped out. Today, Cuba’s giant animals include the hutia, a 15-pound rodent, as well as knight anoles, the largest example of their genus.
The island is also home to the world’s smallest bird species—the bee hummingbird. Some mainland species get close to its size, but this species takes tininess to a whole new level: an average male weighs in at less than 2 grams.
Their small size is matched only by their massive appetite, says Dr. Arturo Kirkconnell, curator of birds at the Cuban National Museum of Natural History. “Hummingbirds are highly evolved nectarivores whose diet is about 90 percent nectar,” Kirkconnell says. The birds are fast eaters, too, able to consume their body weight in sugary nectar in just a few hours.
Learn more about amazing Cuban wildlife in the special exhibition ¡Cuba!, now open to the public and free for Members.
Parts of this story originally appeared in the Summer 2016 issue of Rotunda, the Member magazine.