In Mr. Jin Yong's famous martial arts novel "Dragon Babu", there is such a female character, she is strong and strong, but her face is like a nine-year-old child, she is the famous Tong Piaoyun, also known as Tianshan Tong Mu.
This role has caused heated discussions as soon as it came out, after all, everyone wants to be young forever, but until now scientists have not been able to find a way for us humans to never grow up and celebrate Children's Day all our lives. But if we zoom in to the entire biological world, there are many animals that can actually be the prototype of the Tianshan Tong Grandma, and their secret to appearance is the mysterious "juvenile continuation".
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01
Juvenile continuation is juvenile perpetuation?
Juvenile continuation, the word seems to mean to maintain the juvenile appearance, but it actually has the most essential difference from juvenile eternity, that is, the individual with juvenile continuation is capable of reproduction.
For example, the locust is an insect that we are very familiar with, as an incomplete metamorphosis insect, its life goes through three stages: egg, small locust (nymph), and large locust (adult), of which the nymph stage of the small locust seems to look similar to the adult stage of the large locust, but the wings are a little smaller. But if we peek inside their bodies, we will find that the reproductive system of the little locusts is not fully developed, so they are real babies.
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And the other insect, the red firefly, their female individuals are much more magical. Red fireflies are a type of firefly, and in development, their male adults go through four stages: egg, larvae, pupae, and adult. However, adult females do not have a pupal stage, but will remain juvenile. It's just that their reproductive systems are fully developed and can normally accept the mating of males and reproduce offspring.
To sum up, juvenile continuation is a state that has entered the adult state in reproduction, but the physical characteristics are still like the developmental state of juvenile.
02
Can juvenile continuation live longer?
In "Dragon Babu", Tong Piaoyun's life expectancy has been greatly extended because he can often rejuvenate. In nature, the advantages of juvenile continuation to animals are not yet clear.
Hexagonal dinosaurs are a more common pet in the pet market, its scientific name is Mexican blunt salamander, which is an amphibian belonging to the genus of salamander suborder Blunt-mouthed salamander. The wild population, found only in the Lakes Xochimilco and Charco areas on the southern edge of Mexico City, is a critically endangered species of wildlife. All we buy in the pet market are artificially bred breeds.
As a salamander, the Mexican salamander can actually become bare like a giant salamander (that is, a baby fish), but we generally do not see such a thing because they maintain a juvenile continuation.
For most amphibians, such as frogs, they will first use the outer gills to breathe, then the outer gills degenerate, the inner gills form, and finally the inner gills degenerate and lungs form.
But Mexican axolotls maintain a state of breathing with their outer gills throughout their lives, and their nickname, the hexagonal in hexagonal dinosaurs, refers to their hairy outer gills.
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However, if we increase the content of iodine ions in water and inject them with thyroxine, we can also induce them to transform into adults. However, once they become adults, their life expectancy will be greatly shortened, from the original 10~20 years to less than 5 years.
Based on this, biologists believe that juvenile continuation can help some animals reduce the cost of developmental needs, thereby extending lifespan. However, whether this is the only benefit of juvenile continuation in evolution needs further study.
03
Do humans also have juvenile continuation?
Having said all about animals, we can't help but ask, do humans also have juvenile continuation?
Strictly speaking, we humans have no juvenile continuation, only juvenile phenomenon. For example, many primates will undergo skeletal changes after changing from juvenile to adult, but we humans can still retain the characteristics of young children such as large heads, large eyes, and low brow bones when they grow up. In addition, although the learning ability of adults is not as good as that of young children, our learning ability is still among the best compared to other primates at the same stage.
Based on this, some scientists have proposed that our human infancy is actually prolonged, which can make us more capable of learning and thus more adaptable to the environment.
Epilogue:
In fact, there is no need to pursue infantile continuation, no matter how old we are, if we can always maintain a child's mentality, full of enthusiasm and curiosity about the world, then even if we are 80 years old, we are still young!
Produced by: Popular Science China
Author: Shan Shaojie (National Zoological Museum)
Executive Producer: China Science Expo