VOA慢速英语2016 科学家:猴子用木筏横渡海洋

Scientists: Monkeys Used Raft to Cross Ocean  科学家:猴子用木筏横渡海洋

Scientists found seven monkey teeth that became fossils in an area near the Panama Canal. The teeth were more than five million years old. Scientists think that is when the continents of North and South America came together.

They said the teeth belonged to a species they call Panamacebus transitus. When the species lived, South America was not in contact with other continents.

For that reason, South America has a strange variety of mammals. The animals grew and changed in interesting ways because they were separated from other animals.

Jonathan Bloch works at the Florida Museum of Natural History on the University of Florida campus. He said that Panama was farther south than any other place in North America. He said the monkeys might have swum, but probably rode on some kind of a raft.

Surprising discovery

Bloch believes these monkeys were the only mammals that were able to cross the waterway from South America to reach present-day Panama.

The strip of land, known as the Isthmus¹ of Panama, was formed about 3.5 million years ago. That land bridge permitted large numbers of animals to begin walking between the continents in one of the biggest mixing of species on record.

Bloch said learning that monkeys lived in North America that long ago was a surprising discovery. For a long time, scientists thought that monkeys simply did not exist there.

It would be like learning that Australia's kangaroos and koalas live in the wilds of Asia today.

Words in This Story

monkey - n. type of animal that is closely related to apes and humans and that has a long tail and usually lives in trees 

fossil - n.  something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks

mammal - n. a type of animal that feeds milk to its young and that usually has hair or fur covering most of its skin

raft - n. a flat structure that is used for floating or sailing on water

sloth² - n. a type of animal that lives in trees in South and Central America and that moves very slowly

kangaroo - n. an Australian animal that moves by hopping³ on its powerful rear legs

koala- n. an Australian animal that has thick gray fur, large hairy ears, sharp claws for climbing, and no tail

1 isthmus   

n.地峡

参考例句：

• North America is connected with South America by the Isthmus of Panama.巴拿马海峡把北美同南美连接起来。
• The north and south of the island are linked by a narrow isthmus.岛的北部和南部由一条狭窄的地峡相连。

2 sloth   

n.[动]树懒；懒惰，懒散

参考例句：

• Absence of competition makes for sloth.没有竞争会导致懒惰。
• The sloth spends most of its time hanging upside down from the branches.大部分时间里树懒都是倒挂在树枝上。

3 hopping   

n. 跳跃 动词hop的现在分词形式

参考例句：

• The clubs in town are really hopping. 城里的俱乐部真够热闹的。
• I'm hopping over to Paris for the weekend. 我要去巴黎度周末。