Scientists: Monkeys Used Raft to Cross Ocean
Scientists believe a species of monkeys used a raft to cross 160 kilometers of ocean from South to North America about 21 million years ago.
The monkeys are similar to today's capuchins, small monkeys that often perform with humans at the circus.
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.
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 Isthmus 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.
1.known as 被认为是
The resultant defect is known as chromatic aberration.
2.on record 记录在案的；有史以来的
It was the coldest winter on record.
3.long ago 很久以前
That warship laid up long ago.
4.separated from 分开；分离
Her husband only separated from his lady by one of trifling differences.
1.They said the teeth belonged to a species they call Panamacebus transitus.
belong to 属于
I belong to no party.
Remittance and collection belong to the commercial credit.
2.When the species lived, South America was not in contact with other continents.
in contact with 接触；与...有联系
Farm workers frequently come in contact with these insecticides.
Are you in contact with him now?
科学家在巴拿马运河附近发现了七颗猴子牙齿的化石 。这些牙齿的历史可以追溯到500万年前 。科学家认为500万年前，北美和南美陆地开始相连 。
科学家们表示，这些牙齿属于一种名为“Panamacebus transitus”的物种 。该物种出现时，当时的南美并未与任何大陆相连 。
因此，那时的南美生活着各种奇怪的哺乳动物 。该物种逐渐长大，因与其他动物分离，慢慢发生了不可思议的进化 。
乔纳森·布洛赫（Jonathan Bloch）就职于佛罗里达州大学佛罗里达自然历史博物馆 。他说，巴拿马是北美离南美最近的区域 。他说，也许猴子是游过来的，但也有可能是搭乘筏子横渡过来的 。
巴拿马地峡形成于350万年前 。因为这座陆地桥，两块大陆之间得以交换物种，也就出现了史上最大规模的生物迁徙之一的记载 。
布洛赫表示，2100万年前猴子就已在北美生活是一项惊人的发现 。一直以来，科学家都认为北美根本就没有猴子存在 。