-
(单词翻译:双击或拖选)
How Do Whales 'Sing?'
It is one of Earth's loudest sounds in the ocean: the "singing" of whales.
Now scientists think they have an idea of how baleen1 whales do it. They say the large air-breathing sea animals use a special voice box that enables them to make sound underwater.
Scientists say the discovery is based on a very small study. But it will direct future research into how whales communicate.
The new findings are in a study published recently in the scientific publication Nature. Coen Elemans of the University of Southern Denmark and other international scientists studied the voice boxes, or larynxes, of three dead whales from the beaches of Denmark and Scotland. The three were humpback, minke and sei whales. All three are part of the family of baleen whales, a group that includes the blue whale, the largest animal that ever existed on Earth.
Voice box
In the laboratory, the scientists blew air through the voice boxes under controlled conditions to see what tissues might vibrate. They also created computer models of the sei whale's vocalizations and matched them to recordings3 of similar whales taken in the wild.
Whales' ancestors were land animals that moved into the oceans about 50 million years ago. Elemans said the animals' voice box changed over tens of millions of years in order to make sounds underwater.
Baleen whales do not have teeth or vocal2 cords like humans and other mammals. Instead, they have U-shaped tissue in their voice boxes that permits them to breathe a lot of air very quickly. Their voice boxes also contain a large "cushion" of fat and muscle not seen in other animals. Whales "sing" by pushing the tissue against the fat and muscle cushion.
Elemans said baleen whales depend on the production of sound to communicate in the dark of the deep oceans. "For example, humpback females and their calves4 communicate with each other by voice, and humpback males sing to attract females," he added.
Jeremy Goldbogen is a professor of oceans at Stanford University, who was not involved in the research. He said, "This is the most comprehensive and significant study to date on how baleen whales vocalize, a long-standing mystery in the field."
The whale voice boxes tested were from younger animals, not adult males, who do the singing. Because of that, whale expert Joy Reidenberg said further experiments on adult males are needed to confirm the study's findings.
Reidenberg works for the Center for Anatomy5 and Functional6 Morphology at the Icahn School of Medicine at Mount Sinai in New York City. She noted7 that the research is probably as close as we can get to reproducing how whales sing.
"Right now, our technology involves sticking a scope into a whale to see what exactly is vibrating," she said. "Since you're never going to be able to do that in a wild animal, these experiments are the next best thing."
As loud as whales' songs are, the study suggests that whales cannot produce sounds louder than noise from the shipping industry, Elemans said.
"They're really affected9 by (shipping noise) and it significantly reduces their ability to communicate," he said. "There's just no way for them to get louder."
Because some whales sing as a mating call, the shipping industry's interference with those songs is a concern, said Michael Noad. He is director of the Center for Marine10 Science at the University of Queensland in Australia. He also was not part of the Nature study. "For whale populations that are really dispersed11, like the Antarctic blue whales, they might not be able to find mates in a noisy ocean environment," he said. However, whales like humpbacks that gather in big numbers are more likely to ignore such noise pollution.
Words in This Story
baleen –n. a hard material in the mouth of some kinds of whales that permits them to eat very small shrimp12 in the ocean
vibrate –v. to move back and forth13 quickly, often producing sound
vocalization –n. the act of making a sound, such as speech or singing, using the throat
1 baleen | |
n.鲸须 | |
参考例句: |
|
|
2 vocal | |
adj.直言不讳的;嗓音的;n.[pl.]声乐节目 | |
参考例句: |
|
|
3 recordings | |
n.记录( recording的名词复数 );录音;录像;唱片 | |
参考例句: |
|
|
4 calves | |
n.(calf的复数)笨拙的男子,腓;腿肚子( calf的名词复数 );牛犊;腓;小腿肚v.生小牛( calve的第三人称单数 );(冰川)崩解;生(小牛等),产(犊);使(冰川)崩解 | |
参考例句: |
|
|
5 anatomy | |
n.解剖学,解剖;功能,结构,组织 | |
参考例句: |
|
|
6 functional | |
adj.为实用而设计的,具备功能的,起作用的 | |
参考例句: |
|
|
7 noted | |
adj.著名的,知名的 | |
参考例句: |
|
|
8 shipping | |
n.船运(发货,运输,乘船) | |
参考例句: |
|
|
9 affected | |
adj.不自然的,假装的 | |
参考例句: |
|
|
10 marine | |
adj.海的;海生的;航海的;海事的;n.水兵 | |
参考例句: |
|
|
11 dispersed | |
adj. 被驱散的, 被分散的, 散布的 | |
参考例句: |
|
|
12 shrimp | |
n.虾,小虾;矮小的人 | |
参考例句: |
|
|
13 forth | |
adv.向前;向外,往外 | |
参考例句: |
|
|