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.

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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

Wax Worm Caterpillars Have a Taste for Plastic

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Scientists have discovered that wax worms (Galleria mellonella) can digest plastic. (Photo credit: Kuttelvaserova Stuchelova/Shutterstock)

Federica Bertocchini’s discovery that wax worms can eat through plastic happened completely by accident. Bertocchini, an amateur beekeeper, was dismayed to find that her beehives were infested by wax worm caterpillars. After cleaning out the hive, she went to pick up the plastic bags she had placed the pests in, only to find the bags riddled with holes.   [Read more…]

Sweden’s Dedication to Sustainable Living

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Solar power is just one aspect of Sweden’s sustainable development initiatives. (Bohner Images/Getty Images)

Sweden has consistently been ranked as one of the most sustainable countries in the world for several years in a row. How has this Scandinavian country embraced sustainable living? [Read more…]

Go Green When You Clean

natural cleaners

You can make natural cleaning products from simple ingredients you probably already have in your home. (Photo credit: HMH)

We live in a chemical-filled world. Check the label of almost any household product and you will find a long list of hard-to-pronounce chemical names. While these ingredients might make these products effective cleaners, the toxic chemicals they contain could have deleterious affects on human health. Even fetuses are exposed to chemicals in the womb. One study that tested the infant umbilical cord blood found that babies were exposed to over 200 environmental chemicals before they have even been born.

In most cases, household cleaners aren’t required to list specific ingredients on their labels. Consumers who are interested in what they are spraying and wiping around their homes have to track the ingredients down with phone calls to the company that made them or searches of product websites.

Today, consumers are expressing an increased interest for eco-friendly products and are voting with their spending dollars by buying products that are labeled as safer for the environment, or “green.” But did you know that you can make your own natural cleaning products using a few simple ingredients you likely already have in your home? A walk down the cleaning product aisle at any store might make you think that you need a different product for each surface and each room of the house, but this is not true. Many of the same ingredients can be used to clean multiple surfaces. Making your own cleaning products will help you to have cleaner, safer home environment and it will save your family money, too.

Cleaning Windows: A simple recipe of white distilled vinegar and water is all that is needed to clean windows.  Just add 1 tablespoon of vinegar to a quart of water. If the windows require a more powerful cleaner, you can add more vinegar, up to a solution of half vinegar, half water. Even undiluted vinegar can be used in areas where there are tough spots from hard water. The smell of vinegar will disappear shortly after you spray it, but if a fresh scent is preferred, lemon juice can be added.

Polishing Furniture:  A quick natural way to make furniture polish is to put the juice of a lemon into a bowl or container, add one teaspoon of water, and one teaspoon of olive or vegetable oil. Use a soft cloth to lay a thin layer of the mixture onto wood furniture, and then let it sit for a few minutes. Then use a clean dry cloth to both buff the mixture in and remove the excess from the furniture. This mixture will not keep, so make sure to mix up only as much as you will use immediately. Unlike most store-bought furniture polish, it is safe to discard any remaining mixture down the sink.

Deodorizing Rugs:  A quick, easy, and cheap way to remove odors from carpets and rugs is to sprinkle baking soda generously on them. Leave the baking soda on the carpet for at least fifteen minutes, and then vacuum it up. The baking soda will absorb the odor. If you are trying to neutralize a strong odor, sprinkle the baking soda on, use a broom to work it in to the carpet, and then sprinkle more baking soda on top. Leave up to two days if possible. When it is time to clean it up, first use a stiff broom to collect the top layer in a dust pan. Then vacuum up the rest. Vacuuming up a lot of baking soda could damage your vacuum.

Cleaning the Toilet Bowl:  Like cleaning carpets, baking soda is also good for cleaning toilet bowls. Baking soda is mildly abrasive, so it is good for anything that requires scrubbing – from teeth, to pots and pans, to toilet bowls. For toilets, sprinkle the baking soda in the bowl, and use a toilet brush to scrub. For a cleaning solution that has foaming action, a little vinegar can also be added.

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India’s Tiger Sanctuaries

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As of 2014, the worldwide population of Bengal tigers numbered 2226. (Photo credit: Swapan Photography/Shutterstock)

Over a century ago, more than 100,000 Bengal tigers roamed India. Today, there are just over 2200. What caused such a drastic drop in numbers? And what can be done to save the Bengal tiger from extinction? [Read more…]

20 Eco-Friendly Tips to Reduce Your Impact on the Environment

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Earth Day was founded in 1970 by Senator Gaylord Nelson.  (Photo credit: Loskutnikov/Shutterstock)

April 22 marks the 48th annual celebration of Earth Day. Senator Gaylord Nelson of Wisconsin founded Earth Day in 1970 to bring environmental issues to the top of the national agenda. Until then, there were little to no legal or regulatory mechanisms to protect the environment. [Read more…]

Madagascar’s Upside-Down Trees

(Photo credit: Gil.K/Shutterstock)

Madagascar is home to six of the world’s eight species of baobab trees. (Photo credit: Gil.K/Shutterstock)

The baobab is a tree with an unusual look. Many compare its appearance to a tree planted upside-down, as it looks like its roots are reaching toward the sky. [Read more…]

Let’s Talk Loons

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Common loons protect their young chicks by carrying them on their back. (Photo credit: Roberta Olenick/All Canada Photos/Getty Images)

The echoing call of a common loon across a misty lake is a haunting, ethereal sound. Few who have heard it can soon forget it. Recognizable by their distinctive black and white coloration, loons are common sights during the late spring through early fall months on lakes across the northeastern states and portions of the Upper Midwest. [Read more…]

Australia’s Pickiest Eater

koala

Koalas, one of nature’s pickiest eaters, choose to only dine on eucalyptus leaves. (Photo credit: Purestock/Getty Images)

Many people have favorite foods. But the koala takes “favorite food” to the extreme. These Australian marsupials have evolved to live almost exclusively on eucalyptus leaves. And if that isn’t picky enough, recent research suggests that koalas are highly selective as to the species of eucalyptus they prefer and even the individual trees from which they choose to eat. How have these animals become so picky, and how can scientists use this information to aid in koala conservation efforts?

Filling a Niche

In ecological terms, the highly-selective diet of the koala makes them a specialist, that is, a consumer that primarily eats one specific organism or a very small number of organisms. Specialist species are generally sensitive to environmental changes, especially changes that affect the availability of their food source. However, the pickiness of koalas is likely an evolutionary adaptation.

Eucalyptus trees are the dominant trees of Australia. In fact, there are more than 700 species in the genus Eucalyptus, and most are native to Australia. However, the leaves of these trees are actually very low in protein, not easily digested, and contain compounds that are toxic to most species. Therefore, the ability for koalas to specialize in eating eucalyptus leaves has allowed them to fill an ecological niche. Koalas have virtually no competition for their preferred food source.

Koalas spend approximately 18-20 hours each day sleeping, and most of the remaining time is spent eating. They eat about 500 grams of eucalyptus leaves each day. A number of adaptations allow koalas to digest this food efficiently:

  • Powerful jaws allow the koala to chew the leaves into a very fine paste.
  • The koala’s liver is able to deactivate the toxic compounds found in eucalyptus leaves.
  • A portion of the koala’s large intestine is greatly enlarged to maximize the amount of nutrients extracted.

Studying Feeding Preference

Recent research has focused on finding what characteristics of eucalyptus leaves make them tasty for koalas. In one study, scientists tested a variety of leaves on captive koalas and recorded how much they ate. By analyzing the chemical composition of the leaves that koalas preferred, these scientists found that koalas ate less when the leaves provided to them were high in certain chemicals called formylated phloroglucinol compounds, or FPCs.

The next step in this study was to track wild koalas in a eucalyptus woodland. The scientists found that they were able to use the taste preferences of the captive koalas, based on chemical composition, to predict the tree preference of wild koalas. In addition, the scientists found that koalas spent more time in larger trees that were surrounded either by smaller, less-tasty trees or by larger trees that were equally tasty. Using this combination of leaf chemistry, tree size, and spatial environmental data, scientists hope to map koala habitats based on habitat quality, as a koala would see it.

The Future of Koala Habitats

All of this koala habitat mapping may prove very useful as the concentration of carbon dioxide continues to increase in the atmosphere. Other laboratory studies have shown that increases in carbon dioxide cause the concentration of toxins or compounds that otherwise interfere with digestion in eucalyptus leaves to increase. By studying how increased concentrations of carbon dioxide would affect the chemical composition of various Eucalyptus species, scientists may be able to predict which areas contain habitat that would most likely be of high quality for koalas in the future, and work to protect these areas.

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The Demise of the Cavendish Banana

bananas

The Cavendish variety accounts for nearly 100% of the bananas imported around the world. (Photo credit: Muellek Josef/Shutterstock)

Whether sliced into a bowl of cereal, split in two and served with ice cream, or peeled and eaten, the banana is a common part of the American diet. Americans eat more bananas annually than oranges and apples combined. Bananas are an excellent source of vitamins, including B6 and C, magnesium, potassium, and fiber. While Americans typically view bananas as a snack food, in other parts of the world, they hold a much more important nutritional role. In some areas of Africa, where more than 200 species of the fruit are grown, bananas account for 80% of consumed calories. However, the banana that you know and love – a variety called the Cavendish – is in danger of being wiped out by a catastrophic disease currently spreading across the globe.

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