Frog Can Control Its Blood Flow to 'Disappear'
2023-01-03
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1Some frogs found in South and Central America have the unusual ability to turn on and off their nearly clear, or transparent, appearance.
2During the day, these frogs sleep by going underneath tree leaves.
3Their small bodies do not create shadows, making them almost invisible to birds and other predators that might consider them food.
4But when northern glass frogs wake up and move in search of insects and mates, they take on a partly clear, reddish-brown color.
5Researchers recently published the findings in Science.
6Junjie Yao of Duke University was a co-writer of the study.
7"When they're transparent, it's for their safety," Yao said about the frogs.
8When the creatures are awake, they can escape predators.
9But when they are sleeping, they are more likely to be eaten.
10Yao explained, "They have adapted to remain hidden."
11Adapt means to change one's appearance or behavior in order to live in a place or situation.
12Using light and special imaging technology, the researchers discovered the frogs' secret.
13While asleep, the frogs move, or "hide," nearly 90 percent of their red blood cells in their liver.
14Because they have clear skin and other tissue, it is the blood moving through their bodies that would otherwise give them away.
15The frogs also shrink and pack together most of the organs inside their body, Yao said.
16The 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.
17Exactly how the frogs carry out these changes, and why it does not kill them, remains unknown.
18For most animals, having very little blood for several hours would be deadly.
19But somehow, the frogs survive.
20Further 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.
21Only 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.
22"Transparency is super rare in nature, and in land animals, it's essentially unheard of outside of the glass frog," White said.
23Those that are transparent include some fish, shrimp, jellyfish, worms and insects - none of which move large quantities of red blood through their bodies.
24Frogs seem to be the only creatures able to hide blood while sleeping.
25White used the term dynamic, meaning always active or changing, to describe the frogs' ability.
26"It's just this really amazing, dynamic form of camouflage," he said.
27I'm John Russell.
1Some frogs found in South and Central America have the unusual ability to turn on and off their nearly clear, or transparent, appearance. 2During 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. 3But when northern glass frogs wake up and move in search of insects and mates, they take on a partly clear, reddish-brown color. 4Researchers recently published the findings in Science. 5Junjie Yao of Duke University was a co-writer of the study. 6"When they're transparent, it's for their safety," Yao said about the frogs. 7When 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." 8Adapt means to change one's appearance or behavior in order to live in a place or situation. 9Using 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. 10Because they have clear skin and other tissue, it is the blood moving through their bodies that would otherwise give them away. 11The frogs also shrink and pack together most of the organs inside their body, Yao said. 12The 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. 13Exactly 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. 14Further 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. 15Only 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. 16Those 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. 17White used the term dynamic, meaning always active or changing, to describe the frogs' ability. 18"It's just this really amazing, dynamic form of camouflage," he said. 19I'm John Russell. 20Christina Larson reported on this story for the Associated Press. John Russell adapted it for VOA Learning English. 21_______________________________________________________________ 22Words in This Story 23transparent - n. able to be seen through 24clot- v. to become thick and partly solid : to develop clots 25conceal - v. to hide (something or someone) from sight 26camouflage - 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