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An uphill climb: scientists discover that animals are moving up a mountain in Madagascar.

While hauling packs of supplies on their backs, Christopher Raxworthy and his team have been walking for days. He is hiking up the highest mountain in Madagascar, an island nation off the east coast of Africa. The nearest village is days away. Their only company: swarms of tiny biting flies. "They get into your clothing and eyes and nostrils," he says.

Despite the challenges, Raxworthy is back making the climb a second time. Ten years earlier, the reptile and amphibian expert from the American Museum of Natural History studied animals in the mountain's forests. Now he is back to take another look. Raxworthy uncovers a surprise: Many creatures are on the move. Raxworthy says it's a sign that something is changing on the mountain. These changes may be putting the animals at risk.


As they hike up the mountain, Raxworthy's team stops at various heights. At each spot, they search for reptiles and amphibians. They record which animals live in each area. Raxworthy becomes concerned when he notices that some of the species he spotted on his first trip are missing. "When you return to a site, you expect to see what you found before," he says.

But as Raxworthy climbs higher, some of the species reappear. The move is unusual because these animals are adapted to survive in specific environments. One wouldn't expect a group of species to find a new home so quickly. "Over just 10 years, species moved uphill to an elevation 19 to 51 meters (62 to 167 feet) higher," says Raxworthy. "That's quite a shift."


Raxworthy says the animals may be moving uphill because of global warming. Scientists have determined that people contribute to this gradual rise in Earth's temperature when they burn fossil fuels to create energy. The process releases heat-trapping gases into the air, causing the planet to warm. In the time between Raxworthy's trips, the average annual temperature in Madagascar's capital rose between 0.1[degrees]C and 0.37[degrees]C.


Warming temperatures can kill off reptiles and amphibians by changing their habitats or making them more vulnerable to certain diseases. To survive, the animals move uphill to cooler temperatures.


Not all of the animals can relocate. Those already living near the top of the mountain "have nowhere else to go," Raxworthy says. As a result, they may die out. Two species of frogs that the team found near the mountaintop on the first trip were not found the second time around.

Raxworthy's research shows that if temperatures continue to rise, some animals may die out. He says people can help protect the animals by preventing further global warming. If people use less fossil fuel-based energy and turn to other energy sources, like solar power, it may keep Earth's temperatures from rising much higher. "The important thing is that we can fix this problem, but there is not much time," he says.




Words to Know

Reptile--An animal that has a backbone, skull, and skin that is covered in scales or hard plates.

Amphibian--An animal that has a backbone, skull, and moist skin. Many amphibians begin life in the water and live on land as adults.

Global warming--The long-term increase in the average temperature of Earth's atmosphere.

Fossil fuels--Fuels that are made from the ancient remains of plants and animals. Oil, coal, and natural gas are fossil fuels.

A Malthe's chameleon opens its mouth when it feels threatened.

check it out

Amphibians were the first vertebrates to live on land. Now, up to a third of these animals are threatened with extinction because of a fungus that infects their skin. Amphibians throughout the world have been dying from chytridiomycosis, the disease caused by the fungus.

You can learn more about the evolution, anatomy, and behavior of spotted salamanders and poison dart frogs, as well as sea turtles and Komodo dragons, by asking your teacher or visiting the Hall of Reptiles and Amphibians at the American Museum of Natural History (

Web Connection

For more information on reptiles and amphibians, visit /superscience.



Set a Purpose

Learn how a changing climate is causing reptiles and amphibians in Madagascar to seek cooler mountain climes.


* A reduction in the population of animals like frogs can have serious implications for humans. Some reptiles and amphibians are major insect predators. An unchecked insect population would threaten public health and food supplies. For example, mosquitoes are carriers of disease. And an increased number of mosquitoes could lead to more cases of illness like malaria and dengue fever.

* Besides climate change, amphibians are suffering from another threat--a fungus called chytrid. This deadly fungus is wiping out large numbers of amphibians, particularly in areas of Central and South America. To protect at-risk species, scientists are working on a cure and are harvesting frogs to keep in captivity until it's safe to return them to the wild.

Discussion Question

* When an animal species dies out or is removed from an area, it causes changes up and down the food chain. Write out a food chain for either a water or land ecosystem. How would the ecosystem be affected if you crossed out a type of animal in the chain? (Answers will vary.)


Discussion Question

* Christopher Raxworthy says, "When you return to a site, you expect to see what you found before." What does it mean if the scientist discovers changes?

(Answers may vary but can include: Changes to a site between a scientist's visits can indicate that some kind or factor is changing the environment.)


* /ReptilesAmphibians/default.cfm Visit this site for more information on reptiles and amphibians, as well as links to puzzles, games, and fact sheets.
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Title Annotation:life science
Author:Norlander, Britt
Geographic Code:6MADA
Date:Mar 1, 2010
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