Sweden’s Dedication to Sustainable Living

solar power in Sweden

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…]

India’s Tiger Sanctuaries

Bengal tigers

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…]

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…]

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.

More to Explore

The 411 on Fjords

(Photo credit: Stefan Auth/imagebroker RF/Photolibrary)

Fjords are a spectacular part of the Norwegian landscape. (Photo credit: Stefan Auth/imagebroker RF/Photolibrary)

Fjord is a Norwegian word describing a long, narrow inlet of water with steep cliffs on either side. Norway has the world’s highest concentrations of fjords. [Read more…]

Cameroon’s Mysterious Crater Lakes

(Photo credit: Harri's Photography/Flickr Open/Getty Images)

Though picturesque, some crater lakes hide a deadly secret. (Photo credit: Harri’s Photography/Flickr Open/Getty Images)

August 21, 1986 started out as a normal day near Cameroon’s Lake Nyos. By the end of the day, however, 1746 people and 3500 livestock in the area would be dead. The cause of the catastrophe was, of all things, an exploding lake. But what caused the lake to explode? More importantly, could it happen again? [Read more…]

Harnessing Earth’s Energy in Iceland

Iceland geothermal plant

Geothermal energy is a significant part of Iceland’s renewable energy program. (Photo credit: naten/Shutterstock)

Iceland is known for its dramatic fire and ice landscape. Visitors come from all over the world to soak in the island nation’s thermal pools, which are heated naturally by underground plumes of magma. However, this geothermal energy is harnessed for more than just recreational purposes – it is also used as an important source of renewable energy in the country and even beyond its borders.   [Read more…]

Gwynt y Môr Wind Farm

wind turbines

Gwynt y Môr is the second largest offshore windfarm in the world. (Photo credit: philipbird123/Fotolia)

Gwynt y Môr (which translates to “wind of the sea” in English) is the second largest offshore wind farm in the world. It is located about 13 kilometers (8 miles) off the coast of north Wales near Colwyn Bay and covers an area of 80 square kilometers (about 30 square miles). [Read more…]

The Plight of the Tasmanian Devil

Tasmanian devil

Tasmanian devils are currently threatened by a cancerous facial disease. (Photo credit: ©FiledIMAGE/Shutterstock)

Tasmania, an island located off the southeastern coast of Australia, is home to the Tasmanian devil. Unlike the human adult sized cartoon version, the real Tasmanian devil is only 20-31 inches (51-79 cm) tall and weighs between 9 and 26 pounds (4-12 kg).

While fossil evidence indicates that Tasmanian devils were once found on the Australian mainland, research indicates that the animals went extinct there 400 years ago due to increasingly arid conditions and the spread of the dingo, a type of wild dog. Tasmanian devils were nearly hunted to extinction on Tasmania during the late 1800s and early 1900s as they were considered to be pests by early settlers. The animals were placed under formal legislative protection in June 1941.

Though the Tasmanian devil bears no resemblance to its cartoon counterpart, it does share its terrible disposition. When the animal feels threatened, its puts on an aggressive display of growling, lunging, and baring its teeth. It earned its “devil” name from early settlers after hearing its “otherworldly” scream. However, while it may be aggressive to potential predators, Tasmanian devils tend to be fairly timid and are typically not a threat to people.

Tasmanian devils are nocturnal animals, which means they are active at night. They are carnivorous and generally feed on birds, snakes, fish, insects, and the remains of dead animals. They do not let any food go to waste – they eat the bones, tissue, muscles, and organs of their prey.

Like kangaroos and wombats, Tasmanian devils are marsupials. The animals breed once a year in March. After a three-week gestation period, between 20 and 30 rice-sized young are born. The young, called imps, must race to their mother’s pouch to claim one of her four teats; the majority are too slow and do not survive. The young devils stay in their mother’s pouch for four months, after which they are carried on their mother’s back. The young are fully grown after about nine months.

While in the mid 1990s, there was a surge in the Tasmanian devil population, that time period also coincided with the appearance of a disease called devil facial tumor disease (DFTD). This cancerous disease causes tumors to form on the animal’s face, which makes it difficult for it to eat, leading to starvation. Since 2001, the Tasmanian devil population has declined 60 percent.

Scientists are working to save the species from extinction. To do so, they are sequestering healthy populations to prevent the spread of disease. They are also focusing on captive-breeding programs. Currently, over 20 Australian organizations are involved in captive-breeding efforts and more than 600 Tasmanian devils have been bred in captivity.

More to Explore
Tasmanian Devil Natural History
Tasmanian Devil FAQs
Save the Tasmanian Devil
National Geographic: Tasmanian Devil

Country: Australia
Location: Australia is located on the Oceania continent, which is found between the Indian Ocean and the South Pacific Ocean.
Area: 7,741,220 sq km (land and water) (slightly smaller than the 48 contiguous United States)
Climate: Arid to semi-arid; temperate in the southern and eastern portions of the country and tropical in the northern portions of the country
Terrain: Mainly low desert plateaus; fertile plains in the southeast
Natural Resources: bauxite, coal, copper, diamonds, gold, iron ore, lead, natural gas, nickel, silver, tungsten, uranium, petroleum
Economics: $998.3 billion (est. 2013)
Environmental Issues: Soil erosion, urbanization, desertification, habitat destruction (land and marine)
Source:
CIA – The World Factbook

Scientists Solve Mystery of Deadly 1952 London Fog

double-decker bus in London fog

Visibility was reduced to less than three feet in parts of the city during the killer London Fog event of 1952 (Photo credit: Bettmann/Getty Images)

Though London is well known for its overcast and foggy weather, the fog that enveloped the city for four days in 1952 was a fog like no other. By the time the fog lifted, at least 4000 people were dead and more than 100,000 people had been hospitalized. In addition, thousands of animals, including many livestock, also died. What caused this particularly deadly fog has long been unknown. Now scientists think they have finally solved the mystery behind the killer fog. Their findings may help prevent a similar event from occurring in modern-day China, which is home to 16 of the 20 most polluted cities in the world. [Read more…]