VOA科学技术2023 青蛙可以控制自己的血液流动“消失”（在线收听）

Frog Can Control Its Blood Flow to ‘Disappear’

青蛙可以控制自己的血液流动“消失”

Some frogs found in South and Central America have the unusual ability to turn on and off their nearly clear, or transparent, appearance.

在南美洲和中美洲发现的一些蛙类具有不同寻常的能力，能够打开和关闭它们近乎透明的外表。

During the day, these frogs sleep by going underneath tree leaves. Their small bodies do not create shadows, making them almost invisible to birds and other predators that might consider them food.

白天，这些青蛙在树叶下睡觉。它们的小身体不会产生阴影，使它们几乎不被鸟类和其他可能认为它们是食物的捕食者所察觉。

But when northern glass frogs wake up and move in search of insects and mates, they take on a partly clear, reddish-brown color.

但是，当北方玻璃蛙醒来并移动寻找昆虫和配偶时，它们呈现出部分清晰的红棕色。

Researchers recently published the findings in Science.

研究人员最近在《科学》杂志上发表了这一发现。

Junjie Yao of Duke University was a co-writer of the study.

杜克大学的姚俊杰是这项研究的共同作者。

"When they're transparent, it's for their safety," Yao said about the frogs.

“当它们是透明的，这是为了它们的安全，”姚明谈到青蛙时说。

When the creatures are awake, they can escape predators. But when they are sleeping, they are more likely to be eaten. Yao explained, "They have adapted to remain hidden."

当这些生物清醒时，它们可以逃脱捕食者。但当它们睡觉时，它们更有可能被吃掉。姚明解释道：“他们已经适应了隐藏。”

Adapt means to change one's appearance or behavior in order to live in a place or situation.

适应意味着改变一个人的外表或行为，以便生活在一个地方或环境中。

Using light and special imaging technology, the researchers discovered the frogs' secret. While asleep, the frogs move, or "hide," nearly 90 percent of their red blood cells in their liver.

利用光线和特殊的成像技术，研究人员发现了青蛙的秘密。睡觉时，青蛙会移动或“隐藏”肝脏中近90%的红细胞。

Because they have clear skin and other tissue, it is the blood moving through their bodies that would otherwise give them away.

因为它们有透明的皮肤和其他组织，所以血液在它们体内流动，否则它们就会被泄露出去。

The frogs also shrink and pack together most of the organs inside their body, Yao said.

姚说，青蛙也会收缩，将体内大部分器官聚集在一起。

The research "beautifully explains" how "glass frogs conceal blood in the liver to maintain transparency," said Juan Manuel Guayasamin of University San Francisco of Quito, Ecuador. He was not involved in the study.

厄瓜多尔基多旧金山大学的胡安·曼努埃尔·瓜亚萨明（Juan Manuel Guayasamin）表示，这项研究“完美地解释”了“玻璃蛙如何将血液隐藏在肝脏中以保持透明度”。他没有参与这项研究。

Exactly how the frogs carry out these changes, and why it does not kill them, remains unknown. For most animals, having very little blood for several hours would be deadly. But somehow, the frogs survive.

青蛙究竟是如何进行这些变化的，以及为什么它不会杀死它们，仍然不得而知。对于大多数动物来说，几个小时内血液很少是致命的。但不知怎么的，青蛙活了下来。

Further research on the species could provide useful information for the development of medicines that prevent blood from clotting, said Carlos Taboada of Duke University, a co-writer of the study.

杜克大学（Duke University）的卡洛斯·塔博达（Carlos Taboada）是这项研究的共同作者之一，他表示，对该物种的进一步研究可以为开发防止血液凝固的药物提供有用的信息。

Only a few animals, mostly creatures that live in the ocean, are naturally transparent, said Oxford University biologist Richard White, who was not involved in the study. "Transparency is super rare in nature, and in land animals, it's essentially unheard of outside of the glass frog," White said.

牛津大学生物学家理查德·怀特（Richard White）表示，只有少数动物，主要是生活在海洋中的生物，是天然透明的。怀特没有参与这项研究。怀特说：“透明度在自然界中非常罕见，在陆地动物中，除了玻璃蛙之外，这基本上是闻所未闻的。”。

Those that are transparent include some fish, shrimp, jellyfish, worms and insects — none of which move large quantities of red blood through their bodies. Frogs seem to be the only creatures able to hide blood while sleeping.

那些透明的动物包括一些鱼、虾、水母、蠕虫和昆虫，它们都不能通过身体输送大量的红色血液。青蛙似乎是唯一能在睡觉时藏血的生物。

White used the term dynamic, meaning always active or changing, to describe the frogs' ability.

怀特用“动态”这个词来形容青蛙的能力，意思是总是活跃或变化。

"It's just this really amazing, dynamic form of camouflage," he said.

他说：“这是一种非常惊人的、动态的伪装形式。”。

Words in This Story

transparent – n. able to be seen through

clot– v. to become thick and partly solid : to develop clots

conceal – v. to hide (something or someone) from sight

camouflage – n. something (such as color or shape) that protects an animal from attack by making the animal difficult to see in the area around it