VOA科学技术2023 全身透明的青蛙你见过吗?（在线收听）

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青蛙具有不同寻常的能力，它们能够打开和关闭其近乎透明的外表。

During the day, these frogs sleep by going underneath tree leaves.

白天，这些青蛙在树叶下睡觉。

Their small bodies do not create shadows, making them almost invisible to birds and other predators that might consider them food.

它们小小的身体不会产生影子，从而使得鸟类等可能会把它们当作食物的捕食者几乎看不见它们。

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

但当北方玻璃蛙醒来并四处寻找昆虫和配偶时，它们会呈现出不透明的红棕色。

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合著者之一。

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

姚俊杰在谈到玻璃蛙时说：“它们变透明是为了它们的安全。”

When the creatures are awake, they can escape predators.

当这些生物醒着的时候，它们可以躲避捕食者。

But when they are sleeping, they are more likely to be eaten.

但当它们睡着的时候，它们更有可能被吃掉。

Yao explained, "They have adapted to remain hidden."

姚俊杰解释说：“它们已经适应了隐藏。”

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

Adapt的意思是某物为了在一个地方或环境下生活而改变其外表或行为。

Using light and special imaging technology, the researchers discovered the frogs' secret.

利用光和特殊成像技术，研究人员发现了玻璃蛙的秘密。

While asleep, the frogs move, or "hide," nearly 90 percent of their red blood cells in their liver.

在睡觉时，玻璃蛙会移动或“隐藏”近90%的红细胞在肝脏中。

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，所以血液流经它们的身体时会使它们暴露。

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

姚俊杰说，玻璃蛙还会收缩并将体内的大部分器官挤在一起。

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.

厄瓜多尔旧金山基多大学的胡安·曼努埃尔·瓜亚萨明说，这项研究“很好地解释了玻璃蛙是如何将血液隐藏在肝脏中以保持透明的”。

He was not involved in the study.

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.

玻璃蛙究竟是如何进行这些变化的以及为什么这样做不会杀死它们，目前尚不清楚。

For most animals, having very little blood for several hours would be deadly.

对大多数动物来说，连续几小时血液不循环是致命的。

But somehow, the frogs survive.

但不知何故，玻璃蛙活了下来。

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.

杜克大学的卡洛斯·塔博阿达是这项研究的合著者之一，他说，对该物种的进一步研究可能会为开发防止血液凝结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.

牛津大学生物学家理查德·怀特没有参与这项研究，他说，只有少数动物是天然透明的，它们大多数生活在海洋中。

"Transparency is super rare in nature, and in land animals, it's essentially unheard of outside of the glass frog," White said.

怀特说：“透明在自然界中是极其罕见的，而在陆地动物中，除了玻璃蛙之外，几乎闻所未闻。”

Those that are transparent include some fish, shrimp, jellyfish, worms and insects — none of which move large quantities of red blood through their bodies.

透明的生物包括一些鱼、虾、水母、蠕虫和昆虫——它们体内都没有大量的红色血液。

Frogs seem to be the only creatures able to hide blood while sleeping.

玻璃蛙似乎是唯一一种能够在睡觉时隐藏血液的生物。

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

怀特用“dynamic”一词来描述玻璃蛙的能力，dynamic的意思是总是活跃或不断变化。

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

他说：“这是一种令人惊叹的、动态的伪装形式”。

I'm John Russell.

约翰·拉塞尔为您播报。