Animal life is abundant and diverse in the Virgin Islands, especially under and around the sea. Coral reefs are the epicentre of the underwater environment, and here you will find a diverse array of life forms. On land, you will see birds, reptiles, amphibians.
There are some 386 square miles of coral reef in the Virgin Islands, more than twice the total landmass of the territories. The Horseshoe Reef around Anegada, in the British Virgin Islands, is one of the largest barrier reefs in the world. Buck Island, near St. Croix, is surrounded by 31 square miles of barrier reef.
The most common type of reef in the Virgin Islands is the fringing reef, which runs parallel to the shore, providing protection for coastal areas. In other places, coral has begun to grow on underwater rocks and other hard surfaces.
Home to some two million plant and animal species, coral reefs are the most biologically diverse ecosystem in the ocean and the second most diverse in the world—only the tropical rainforest supports more plant and animal species.
There are almost a thousand different coral species, each with its own growth and reproduction pattern. Each also has its own unique style: Some resemble wrinkled brains and mushrooms, while others look like pillars, tabletops, moose antlers, wire strands, or cabbages.
Coral reefs provide a habitat for a wide range of sea creatures, including mollusks and urchins. Sea fans, anemones, and sponges fasten onto the coral. Small creatures find nourishment and protections amid the coral, and in turn attract large sea species like sea turtles, rays, and sharks.
The building block of the coral reef is the coral polyp, a tiny, soft creature that attaches itself to hard surfaces in shallow sea areas. Polyps can range from the size of a pinhead to that of a football. The polyps have slit-like “mouths” at their top, surrounded by tentacles, which they use to sting and trap food—mainly plankton. Cells on the bottom of the polyps produce calcium carbonate, which builds islands and reefs. When a polyp dies, it hardens into “rock,” creating the reefs that we know.
Coral reefs grow slowly. While some reefs can grow as much as two feet per year, most grow only a few inches. Some of the coral reefs that exist in the Virgin Islands have been growing for millions of years.
Small algae called zooxanthellae live symbiotically within coral polyps. The algae get shelter and food from the polyp, while the polyp gets food from the algae via photosynthesis. Photosynthesis requires sunlight, so coral reefs can only grow where the ocean is shallow and clear. Coral also requires ocean currents, which bring it plankton, the tiny organisms that sustain it, and warm ocean temperatures—between 75 and 85 degrees.
The polyps and algae are a food source for other sea creatures, and the reef’s caves and crevices are ideal locations for breeding and protection from large predators. More than one-quarter of all marinelife is found in coral reefs.
Life on the reef
Coral reefs are cities under the sea. Even when the surface of the sea is glassy and there is not a sound except the wind, the underwater reef is teeming with life. It is a joy to float above and observe.
There are two main types of coral: hard coral and soft coral. Hard coral, the bricks and mortar of the coral reef, takes on a fantastic array of shapes and colors. Elkhorn coral looks like clusters of antlers reaching out sideways toward the surface of the ocean. Brain coral colonies are spheres imprinted with a pattern that makes them look remarkably like brains. Pillar corals grow like candelabras reaching to the sea surface, and staghorn coral looks like great colonies of orange starfish. Pay particular attention to fire coral, yellow stony coral that looks something like giant lichen. A brush against one of these can leave you with painful “burns”.
Like hard coral, soft coral is made up of colonies of coral polyps. But unlike hard corals, soft corals have skeletons consisting of needles encased in softer, more flexible material. Sea fans are a common kind of soft coral. Others resemble whips and plumes.
A host of other sea creatures live among the coral. Sea anemones are soft, translucent tentacled creatures often seen anchored in cracks between the reef. The sharp, black barbs of sea urchins can easily be seen poking out from under and between rocks. There are many types of sea sponges—soft, multicellular animals that act as filters for the ocean. Crustaceans including lobsters and crabs are also found on the reef, often beneath a dark ledge. It takes a practiced eye to find these reclusive animals.
Fish, of course, are the star of the show on the coral reef. They dart around, nibbling, weaving in and out of the current, showing colors ranging from deep purple to bright yellow and every hue in between. One of the most common reef fish is the parrot fish, which comes in colors ranging from red to rainbow to black. Look closely and you will see its distinctive fused teeth, which it uses to scrape chunks of coral into its mouth. Using a mill at the back of its throat, the parrot fish grinds the coral into a powder, which is excreted as sand.
The yellowtail damselfish begins life a vivid shade of dark blue with bright blue spots before turning to a nondescript brown as an adult. Look for the feelers on the lower lip of the goatfish. One of the most common types of reef fish is the wrasse, a small fish which often has bright stripes of color near its head. Triggerfish, one of many types of fish that can change colors based on its surroundings, are distinguished by their tails, which extend to two long points.
Some fish have very distinctive shapes. Trunkfish are easy to spot because of their triangular build. Long and thin, the trumpet fish eats by sucking unsuspecting fish into its vacuum-like mouth. You will often encounter them standing on their heads to mimic some part of the underwater landscape. Colorful angelfish are flat and can grow to be the size of a dinner plate. They swim elegantly around the reef and will surely catch your eye. Butterfly fish resemble angelfish but are distinguishable by a large black dot near their tails, meant to confuse predators.
Look out for squid, easily recognized by their large white eyes, which look almost human. Most reef squid are small—about a foot long—and can be seen swimming around just like a fish. The octopus, on the other hand, often hides.
One of the greatest joys of snorkeling on the reef is seeing a school of fish. Near shore, you may find yourself engulfed in a mass of tiny fry. Pop your head above water and you will no doubt see pelicans diving for dinner. On the reef, schooling species include goatfish, grunts (named for a noise they make), and spadefish. You may also encounter schools of jacks and silversides.
You will also see larger sea creatures on the coral reef, attracted by the presence of so much potential food. Hawksbill turtles, one of the three kinds of sea turtle in the Virgin Islands, look for food and shelter around the reef. Green turtles prefer sea grass beds, and leatherbacks are most often seen in the open ocean.
The only indigenous mammal in the Virgin Islands is the bat. All others were introduced by people who migrated through and eventually settled in the islands. Pre-Columbians introduced dogs, pigs, guinea pigs, and agoutis (although the latter two have not survived in the wild). European settlers introduced a wide range of domesticated animals, including goats, sheep, horses, and white-tailed deer.
Europeans are also responsible for two of the islands’ worst pests: the rat, which arrived as a stowaway on ships, and the mongoose, introduced to kill rats that had taken up residence in sugarcane fields. The mongoose was a disappointment to rat control; it was active during the day (while rats slept) and could not climb trees in pursuit of the more agile rodents. Instead, mongooses fed on lizards, birds, turtle eggs, and chickens. They have been responsible for wiping out whole species of lizards on some islands. Today, mongooses remain a problem for conservationists and farmers.
Birds are some of the most delightful animals of the Virgin Islands, and birders will be rewarded by the colors, acrobatics, and songs of the island residents.
Near the sea, there is usually no better show than the one put on by pelicans, which glide far above the ocean surface only to crash down with incredible force, gathering tiny fish and other sea creatures in their pouches. Pelicans have special air chambers on their chest and special film over their eyes to cushion the sea landing.
One of the most easily identifiable shorebirds is the magnificent frigate bird, sometimes called a man-o-war. This long-winged black bird with a forked tail and bent wings looks like a holdover from the dinosaur era. Male frigate birds have a strip of bright red skin on their throats, which they blow up like a balloon to attract females during mating season. Frigate birds catch fish at the surface of the sea, but their biggest food source is in the air; they chase other seabirds fiercely until they drop their catch. Then the frigate bird glides down to catch it.
Look out as well for brown boobies, laughing gulls, royal terns, and tropic birds. Boobies, now endangered, got their name from the Spanish word bobo, meaning “dunce.” They are large and excellent divers. Caribbean gulls are smaller than the seagulls many are used to; listen to their song, “ha, ha, ha, ha.” Tropic birds are elegant and beautiful. Look for the long streamers that extend from their tails.
Inland, birds are smaller and much more difficult to watch. Flower gardens tend to attract doctor birds and green-throated caribs. One of the favorite birds of the islands is the bananaquit, a ubiquitous and cheerful creature you will see in flower gardens and the forest. They have a wheezy, squeaky call and build untidy nests of grass and leaves. They often have bright yellow bellies, set off by black around the head.
Many open-air restaurants suffer an abundance of Carib grackles, medium-size birds that make sport of eating crumbs, leftovers, and even whole meals from diners’ plates. There are two kinds of doves on the islands: the common ground dove and the zenaida dove, also called turtledove.
The mascot of the Charlotte Amalie High School athletics department is the chicken hawk. These common hawks can be seen soaring high above farms, fields, and woodland. They keep an eye out for favorite food sources: snakes, lizards, frogs, and rats.
Another bird that is easy to see is the cattle egret, a long-legged white heron that follows cattle, sometimes on their backs. These birds are natives of Africa and were first reported in the Caribbean in 1933.
Reptiles and Amphibians
Many travelers are taken aback by the pulsing, almost deafening, song of the bo-peeps, or coquis, at night. The call of these small frogs is often at first mistaken for the sound of crickets or cicadas. In the rainforest, they sing all day; in drier habitats, they sing only at night. Listen closely, and you will hear that they are saying their name: “ko-kee, ko-kee.”
Less melodious is the song of the giant toad, a brown, blotchy creature that can grow as large as a softball. These toads hide out during the day but often sing the praises of the rain at night.
One of the most delightful animals in the Virgin Islands is the lizard. Newcomers never fail to delight in their omnipresence, agile movement, and—in some cases—impressive shows. The most common kind of lizard is the ground lizard, a small brown lizard that munches on insects. Tree lizards change colors to suit their surroundings, and males have rounded sacs under their throats. When they want to be threatening, the males will inflate their pouch and do “push-ups” in place. The third common type of lizard is the house gecko, or wood slave. These helpful creatures are used to people and are often found inside. House geckos have Velcro-like feet that allow them to climb on just about any surface. They feed on insects (they are great for killing mosquitoes that make it inside) and are active at night.
It is easier to see the zigzagging tracks of the ghost crab than to spot the animal itself, which can scurry sideways so quickly it seems to disappear. Ghost crabs live on the beach, burrowing into the sand for protection and safety. Farther inland, it is the land crab, or white crab, that dominates. These large, whitish crabs have one claw larger than the other and are sometimes eaten. Another very common crab is the hermit crab. Although associated with the sea, these crabs are found miles away from the shore and high up on mountainsides. Many take up residence in the shells of West Indian top snails. When hermit crabs outgrow their shells, they have to find new ones. Hermit crabs will eat just about anything, including rat poison, carrion, and feces. Their flesh is a traditional fish bait.