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VOA慢速英语2013 科学家发现新的物种

时间:2013-08-28 14:01:40

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Scientists Discover New Animal 科学家发现新的物种

From VOA Learning English, this is SCIENCE IN THE NEWS. I’m June Simms.

And I’m Bob Doughty1. Today we tell about a new animal species native to South America. We tell how agricultural chemical products are harming frogs in northern California. And we have a report about elephants and how the night sky could affect the timing2 of their raids on farms.

Meet the new mammal!  The olinguito is new to science, although it has been living in the cloud forests of South America for some time, unknown to researchers.

Scientists say the olinguito is the first new carnivore discovered in the Americas in more than 30 years. It is a hairy orange-brown creature with a sweet face and big eyes. The animal has small, rounded ears and lives in the trees. An adult weighs one kilogram and measures about 75 centimeters, with half of those centimeters taken up by its ringed tail.

The olinguito shares its family roots with raccoons and kinkajous. Most of the time, it likes to eat fruit, although it also eats meat. Active at night, the animal has lived in Colombia and Ecuador for a long time. But the olinguito did not exist in science books before now.

Kristofer Helgen is the curator of mammals at the Smithsonian Institution’s National Museum of Natural History in Washington. He led the research team that confirmed the existence of the olinguito. It had been mistaken more than a century ago for a look-alike animal -- a similar but larger olingo.

“Think about these cloud forests. This animal, like so many animals in the rain forest, only comes out at night. It doesn’t come out of the trees. It’s wet. It’s dark. It’s socked-in with cloud. It’s hard to find these animals.”

But his team succeeded in making the discovery. In the forest, they observed that the olinguito was not just another olingo.

Mr. Helgen had been studying olingos in a museum 10 years ago. At that time, he observed a difference in the size and shape of the heads and teeth. That led him on an effort to prove he was looking at an animal never before described by science.

About 10 years of work led Kristofer Helgen from museum storage areas to cloud forests in South America. He got lucky when he communicated with a zoologist3 in Ecuador. The animal expert there made a short video that scientists say shows an olinguito in the trees. The video confirms that the olinguito is different from the olingo.

Mr. Helgen says even people who live near the olinguitos’ forests do not see it as different from similar animals.

But it seems the world knew an olinguito long before 2013, without knowing it. A female of the species from Colombia was even kept at zoos in the United States during the 1960s and 1970s. But zoo officials thought they were showing an olingo, the similar animal.

Kristofer Helgen spoke4 with the keeper of that olinguito, who told him a sad story. She said the animal was moved from one zoo to the next because she refused to mate with male olingos.

Mr. Helgen says that mating was impossible. The olinguito and the olingo are totally different species. So she was not just choosy.

Mr. Helgen says tens of thousands of olinguitos live in the wild and are not in danger of disappearing forever. Human beings, however, are moving closer to the olinguito habitat in the Andean cloud forests. The research team estimates that 42 percent of historic olinguito habitat has been removed.

The findings were published in the journal ZooKeys.

You are listening to Science in the News from VOA Learning English. With Bob Doughty, I’m June Simms in Washington.

California Parks May Be In Danger

America’s national parks in northern California may look clean and untouched. But scientists are finding that the land could have hidden problems. Researchers say pesticide5 products may have harmed local wildlife, both deep in the forests and up on the mountain tops. They say the pesticides6 came from agricultural operations in the valleys far below.

Researchers with the United States Geological Survey have been catching7 frogs in the mountains of the Sierra Nevada. They tested the frogs for contamination with agricultural pesticides, chemicals used to protect crops.

There is no farming in the national parks. But winds can bring chemicals from farms in California’s Central Valley into the mountains. Kelly Smalling is the lead author of the study. She says pesticides could be harmful to animals like frogs.

“The decline of amphibians9 has been documented for decades and decades. We know that amphibian8 populations are declining. Some populations have gone extinct. And why these populations are declining is still a mystery.”

The researchers also collected samples of pond water and sediments11 from the bottoms of mountain pools. These samples tested clean, or close to it. But the researchers found evidence of 12 different agricultural pesticides in Pacific chorus frogs from the area.

Scientists are concerned about the test results. They suggest that there are harmful pesticides in the bodies of animals that live in protected areas.

“The concentration in the frog becomes greater than the concentration that is present in the water or the sediment10, or some other part of the environment.”

The most common chemical compound in the frogs was DDE, a decomposed12 product of the insecticide DDT. The researchers expected these results. DDT was banned in 1972, but it is a long-lasting chemical.

The team was also surprised by some of the results. They found three pesticides, including two fungicides, in the frogs. All three had never been found in frogs before. And the researchers believe that this is the first time frogs have tested positive for fungicide contamination.

The results of the study show the unexpected ways industry is polluting our planet. Kelly Smalling says the next step is deciding what to do about it.

“The first thing we need to do is understand how these chemicals that we’re finding will impact the frogs. Then we have to start looking at the larger question on how to fix the problem.”

Moon Influences Eating Habits of Elephants

A new study has found that African elephants appear to use darkness to avoid being seen or heard when raiding farmland for food. The study also showed that elephants carry out their food raids based on the appearance of the moon, or lunar cycle. Researchers believe the animals are doing this during the cover of darkness to avoid contact with human beings.

A report on the study appeared in the African Journal of Ecology. Rachel Grant teaches animal behavior at Anglia Ruskin University in England. She says elephants are cathemeral, meaning they are active both day and night. But she says their raids on crops almost always take place at night. This suggests that the animals go near villages when they sense that their huge bodies are more difficult to see.

Ms. Grant added that an elephant’s knowledge of the higher risk of being discovered on moonlit nights could explain its behavior during the lunar cycle.

The study was carried out in and around Mikumi National Park in Tanzania. The park has one of the largest populations of wild elephants in Africa. It is about 300 kilometers west of Dar es Salaam13.

The researchers chose five villages near the wildlife area and counted how many times elephants raided crops. They found that few of elephant “raid nights” took place during a full moon. The amount of crop damage also fell considerably14 during such periods.

Rachel Grant says some elephants have what she calls “an internally arising biological rhythm” or they may be basing their decision-making on local conditions. In her words, “Many animals alter their behavior according to varying light levels and the perceived risk of predation.” She says this rhythm is likely to be a partly evolved, partly learned response.

Ms. Grant says the behavior probably is found in elephant populations in countries other than Tanzania. She adds that information from the study could be used to protect farms from elephant damage.

This Science in the News program was written by Madeline Smith and Jerilyn Watson. I’m June Simms.


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点击收听单词发音收听单词发音  

1 doughty Jk5zg     
adj.勇猛的,坚强的
参考例句:
  • Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质:脾气倔强,性格刚强。
  • The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。
2 timing rgUzGC     
n.时间安排,时间选择
参考例句:
  • The timing of the meeting is not convenient.会议的时间安排不合适。
  • The timing of our statement is very opportune.我们发表声明选择的时机很恰当。
3 zoologist MfmwY     
n.动物学家
参考例句:
  • Charles darwin was a famous zoologist.查尔斯达尔文是一位著名的动物学家。
  • The zoologist had spent a long time living with monkeys.这位动物学家与猴子一起生活了很长时间。
4 spoke XryyC     
n.(车轮的)辐条;轮辐;破坏某人的计划;阻挠某人的行动 v.讲,谈(speak的过去式);说;演说;从某种观点来说
参考例句:
  • They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
  • The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。
5 pesticide OMlxV     
n.杀虫剂,农药
参考例句:
  • The pesticide was spread over the vegetable plot.菜田里撒上了农药。
  • This pesticide is diluted with water and applied directly to the fields.这种杀虫剂用水稀释后直接施用在田里。
6 pesticides abb0488ed6905584ea91347395a890e8     
n.杀虫剂( pesticide的名词复数 );除害药物
参考例句:
  • vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜
  • There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。 来自《简明英汉词典》
7 catching cwVztY     
adj.易传染的,有魅力的,迷人的,接住
参考例句:
  • There are those who think eczema is catching.有人就是认为湿疹会传染。
  • Enthusiasm is very catching.热情非常富有感染力。
8 amphibian mwHzx     
n.两栖动物;水陆两用飞机和车辆
参考例句:
  • The frog is an amphibian,which means it can live on land and in water.青蛙属于两栖动物,也就是说它既能生活在陆地上也能生活在水里。
  • Amphibian is an important specie in ecosystem and has profound meaning in the ecotoxicology evaluation.两栖类是生态系统中的重要物种,并且对环境毒理评价有着深远意义。
9 amphibians c4a317a734a700eb6f767bdc511c1588     
两栖动物( amphibian的名词复数 ); 水陆两用车; 水旱两生植物; 水陆两用飞行器
参考例句:
  • The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
  • Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。
10 sediment IsByK     
n.沉淀,沉渣,沉积(物)
参考例句:
  • The sediment settled and the water was clear.杂质沉淀后,水变清了。
  • Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。
11 sediments 8b3acb612b624abdf2c2881bc6928565     
沉淀物( sediment的名词复数 ); 沉积物
参考例句:
  • When deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后,体积的70-80%是水。
  • Oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。
12 decomposed d6dafa7f02e02b23fd957d01ced03499     
已分解的,已腐烂的
参考例句:
  • A liquid is decomposed when an electric current passes through it. 当电流通过时,液体就分解。
  • Water can be resolved [decomposed] into hydrogen and oxygen. 水可分解为氢和氧。
13 salaam bYyxe     
n.额手之礼,问安,敬礼;v.行额手礼
参考例句:
  • And the people were so very friendly:full of huge beaming smiles,calling out "hello" and "salaam".这里的人民都很友好,灿然微笑着和我打招呼,说“哈罗”和“萨拉姆”。
  • Salaam is a Muslim form of salutation.额手礼是穆斯林的问候方式。
14 considerably 0YWyQ     
adv.极大地;相当大地;在很大程度上
参考例句:
  • The economic situation has changed considerably.经济形势已发生了相当大的变化。
  • The gap has narrowed considerably.分歧大大缩小了。

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