The Sloths of Costa Rica

Costa Rica sloth

Sloths are found throughout Costa Rica’s tropical forests. (Photo credit: Kjersti Joergensen/Shutterstock)

With their shy, seemingly secret-hiding smiles, languid movements, and unique habits, the sloth fits the basic description of a charismatic animal to a T.

These unusual animals can be found in the tropical forests of Central and South America. Their populations are flourishing in their Costa Rican habitat. Sloths can be found in ecosystems throughout this Central American country, except at the highest elevations.

There are two species of sloth found in Costa Rica: Bradypus variegatus, commonly known as the three-toed sloth, and Choleopus hoffmanni, commonly known as the two-toed sloth. Both of their scientific names reflect their slow movement, as Bradypus means “slowness of foot,” and Choleopus means “lameness of foot.” Though they look similar to primates, sloths are actually more closely related to anteaters and armadillos.

Though it was commonly thought that sloths spent most of their time sleeping–previous estimates had sloths spending upwards of 14 hours asleep per day–research from 2008 indicates that these animals actually only sleep 9 to 10 years a day. Scientists think the previous estimates, based on captive populations, overestimated the sloths’ sleep patterns as those sloths lacked the need to be vigilant against predators. In the wild, three-toed sloths are active both day and night, while two-toed sloths are nocturnal.

These animals spend the majority of their lifetimes in the tops of trees. Their slow movement is likely a result of their need to conserve energy due to their extremely slow metabolism. It takes a sloth up to four weeks just to digest a single leaf. Contrast that with humans, who completely digest a meal within a period of 24-44 hours. One of a sloth’s more unique habits is a result of its slow digestion–sloths only relieve themselves once a week. To do so, they climb down to the bottom of the tree where they do their business, losing about 1/3 of their body weight in the process.

One thing that helps sloths avoid predators and blend in with their leafy habitat is the algae that grows on their fur. The species of algae that lives within sloth fur is Trichophilus welckeri, which is found nowhere else. Research indicates that the algae is passed from mother to offspring within a few weeks of its birth. However, a sloth’s fur isn’t just a habitat for algae. It also houses a variety of other insects and fungi. One of the more interesting examples is the pyralid moth (Cryptoses spp.), which relies on the sloth for its entire lifecycle. A sloth’s body could be home to more than 100 moths. The moth spends the majority of its lifetime burrowed deep within the sloth’s fur. The real magic happens when the sloth descends to the base of its tree to do its weekly business. The moths are coprophagous, meaning they eat excrement. Female moths lay their eggs in the sloth’s excrement, and the larvae grow to maturity within the dung before hatching and flying up the tree to find another sloth’s furry back to inhabit.

According to reporting in The New York Times about this phenomenon, “After [the moths] die, their bodies are decomposed by the host of fungi and bacteria in the sloth’s fur. The metabolic products of this decay, especially nitrogen, are the feedstock for the specialist algae that grow in the sloth’s hair shafts. The researchers guessed that the sloths might be eating the algae from their own fur, and that this could be the purpose of the whole system.”

In addition to being unique animals, it appears that the sloth itself is home to a unique ecosystem as well.

More to Explore
Sloth Facts: Habits, Habitat & Diet
National Geographic: Sloth
7 Surprising Sloth Facts
The Sloth’s Busy Inner Life


Country: Costa Rica
Location: Costa Rica is located in Central America. It is bordered by both the Caribbean Sea and the North Pacific Ocean and is located between Nicaragua and Panama.
Area: 51,100 sq km (land and water) (slightly smaller than West Virginia)
Climate: The climate of Costa Rica is tropical and sub-tropical. It has a specific rainy season (May to November) and dry season (December to April).
Terrain: The terrain of Costa Rica features coastal plains separated by rugged mountains, which include over 100 volcanic cones, of which several are major active volcanoes.
Natural Resources: Hydropower
Economics: $57.69 billion (est. 2015)
Environmental Issues: Air pollution, coastal marine pollution, deforestation and land use change, fisheries protection, soil erosion, soil erosion, solid waste management
Source: CIA – The World Factbook

Protecting South Africa’s ‘Megadiversity’

(Photo credit: Jupiterimages/Getty Images)

South Africa is home to a staggering list of plant and animal species. (Photo credit: Jupiterimages/Getty Images)

South Africa is one of 17 countries described as being “megadiverse” by Conservation International, a nonprofit environmental organization. The country is home to megafauna such as wildebeest, elephants, great white sharks, zebras, lions, and leopards. The country contains 10 percent of the world’s plant species and 15 percent of the world’s marine species. South Africa also has a rich population of endemic species–that is, species that only exist within its borders. Fifty-six percent of its amphibians, 65 percent of its plants, and 70 percent of its invertebrates are found only within South Africa and nowhere else.

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Bitter Lake National Wildlife Refuge, New Mexico

Two cranes take flight over the Bitter Lake National Wildlife Refuge. (Photo courtesy of USFWS)

Roswell, New Mexico is well known for its unusual history. Most people associate Roswell with UFOs and martians, but there is much more to this southeastern New Mexico town than tales of science fiction. The truly unique sight to be found near Roswell is the Bitter Lake National Wildlife Refuge, a 2000-acre internationally-recognized wetland.

Yes—a wetland—sitting on the edge of the Chihuahuan Desert. Great Blue Herons, egrets, and White-faced ibis wade through the shallow, bitter-tasting water that is the only place on Earth where Noel’s amphipod, a tiny freshwater crustacean can survive. A marine alga that is normally found only in lagoons along the edges of the Gulf of Mexico also makes its home here. In addition to this, two endangered snail species, the rare, saltwater-loving Pecos puzzle sunflower, and nearly 500 different species of vertebrates can be found within the boundaries of the refuge.

The wildlife seen within the refuge varies widely with the time of the year. During the winter, tens of thousands of snow geese and sandhill cranes inhabit the wetland, having migrated from colder climates. Autumn and springtime months bring vast flocks of songbirds that stop over for a meal or two on their annual pilgrimages from the north to warmer climates and back again. In the summer, snowy plovers, killdeer, and avocets raise their chicks. And of course, year-round, you’ll find the roadrunner, the state bird of New Mexico, as well as red-winged blackbirds, coyotes, cottontail rabbits, rattlesnakes, and more than 100 species of dragonflies.

Millions of years ago, during the Permian period, a shallow sea covered the area. What remains today is a group of seeps, sinkholes, springs and playa lakes that are fed by an underground river, providing water that can be impossible to find in other parts of the state. Even when severe drought contributed to massive wildfires in 2011, water fowl and a variety of other wildlife found shelter at Bitter Lake.

Since the area around Bitter Lake receives less than 36 cm (14 in.) of rain a year, the availability of water is always a concern, especially since it is one of the most intensively farmed regions in the Roswell basin. Due to this, one of the biggest ecological threats to the refuge includes increased groundwater use and surface water diversion for irrigation. Area residents help the National Park Service fight a constant battle against the presence of the invasive species Tamarix chinensis, commonly known as salt cedar, or Chinese tamarisk. The trees, native to China and Korea, were introduced to the United States as ornamental plants. A single mature tree can absorb up to 200 gallons of water a day, while their stems and leaves secrete salt, which contaminates the soil and kills native plant species. Because each tree can produce hundreds of thousands of seeds each year, these plants pose a major problem within the wildlife refuge.

Bitter Lake’s integral role as a home for a large number of endangered species and as a rest stop for migrating birds has not gone unnoticed. In April 2010, the refuge was recognized as a Wetland of International Importance under Ramsar, a treaty that promotes wetland conservation throughout the world.

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Bitter Lake National Wildlife Refuge
Friends of the Bitter Lake National Wildlife Refuge
Birding at Bitter Lake National Wildlife Refuge, New Mexico

The Impact of Artificial Lights on Wildlife

This composite image shows the world light use at night. (Credit: Data courtesy Marc Imhoff of NASA GSFC and Christopher Elvidge of NOAA NGDC. Image by Craig Mayhew and Robert Simmon, NASA GSFC.)

As shown by this world map, the night sky is obscured by artificial lights in many parts of the world. These lights are used to illuminate buildings, roadways, stadiums, fields, and other structures. While these lights help humans navigate around their surroundings, they can wreak havoc with the natural movements and functions of other animals. Research indicates that the light pollution caused by artificial lights can disorient wildlife, affect natural circadian rhythms, and disrupt bird migration.

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