The "Tianshan Child-like Grandma" of the Animal World: I don't want to grow up...

Produced by: Science Popularization China

Author: Shan Shaojie (National Museum of Zoology)

Producer: China Science Expo

In Mr. Jin Yong's famous martial arts novel "Demi-gods and Semi-Devils", there is a female character who is very powerful but looks like a nine-year-old child. She is the famous Tong Piaoyun, also known as the Child-Father of Tianshan.

This character has aroused heated discussions since its debut. After all, everyone wants to stay young forever, but until now scientists have not found a way for us humans to never grow up and celebrate Children's Day all our lives. But if we expand our vision to the entire biological world, there are many animals that can actually be the prototypes of Tianshan Tonglao, and their secret to staying young is the mysterious "continuation of juvenile state".

Axolotl in a neotenous state (diagram)

(Photo source: veer)

Does the continuation of neoteny mean eternal childhood?

The word "neotyping" seems to mean always maintaining a juvenile appearance, but there is actually an essential difference between it and perpetual juvenility, that is, the individuals in the neotyping state are capable of reproduction.

For example, locusts are an insect that we are very familiar with. As an insect with incomplete metamorphosis, they go through three stages in their life: eggs, small locusts (nymphs), and large locusts (adults). The nymph stage of small locusts seems to look very similar to the adult stage of large locusts, except that their wings are a little smaller. But if we peek inside their bodies, we will find that the reproductive system of small locusts is not yet fully developed, so they are real babies.

locust

(Photo source: veer)

The females of another insect, the red firefly, are much more amazing. The red firefly is a type of firefly. During development, their male adults will go through four stages: egg, larva, pupa, and adult. However, female adults do not have a pupal stage, but will always remain in their juvenile state. It's just that their reproductive system has developed completely, and they can normally accept male mating and reproduce offspring.

Firefly

(Image source: wikimedia)

To sum up, neoteny is a state in which an organism has entered adulthood reproductively, but its physical characteristics still resemble those of a juvenile.

Can neoteny allow one to live longer?

In Demi-Gods and Semi-Devils, Tong Piaoyun's life span is greatly extended because he can often regain his youth. In nature, the advantages of neoteny for animals are still unclear.

The axolotl is a common pet in the pet market. Its scientific name is Ambystoma Mexicana, an amphibian belonging to the genus Ambystoma of the suborder Salamanders. The wild population is only distributed in the Xochimilco Lake and Chalco Lake area on the southern edge of Mexico City. It is a critically endangered wild animal. The ones we buy in the pet market are all artificially bred varieties.

Axolotl (Ambystoma mexicanum)

(Photo source: veer)

As a salamander, the Mexican axolotl can actually become bald like the giant salamander (also known as the Chinese baby fish), but we generally don't see them like this because they maintain a juvenile state.

For most amphibians, such as frogs, they will go through a process of first using external gills to breathe during development, then the external gills will degenerate and internal gills will form, and finally the internal gills will degenerate and lungs will form.

The life cycle of a frog

(Photo source: veer)

But the Mexican axolotl will continue to use external gills to breathe throughout its life. Their nickname - the hexagon in the hexagonal dinosaur - refers to their furry external gills.

However, if we increase the iodine ion content in the water and inject them with thyroxine, we can also induce them to transform into adults. However, once they become adults, their lifespan will be greatly shortened, from the original 10 to 20 years to less than 5 years.

Based on this,** biologists believe that neoteny can help some animals reduce the cost of development and thus extend their lifespan.** However, whether this is the only benefit of neoteny in evolution requires further research.

Do humans also have neoteny?

After talking about so many animals, as Children's Day is approaching, we can't help but ask, do humans also have a neoteny?

(Photo source: veer)

Strictly speaking, we humans do not have neoteny, but only neoteny. For example, many primates undergo skeletal changes when they grow from infancy to adulthood, but we humans can still retain the characteristics of infants, such as large heads, large eyes, and low brow ridges. In addition, although adults' learning ability is not as good as that of infants, compared with other primates at the same stage, our learning ability is still among the best.

Based on this, some scientists have proposed that our human childhood is actually extended, and this extension can enable us to have stronger learning abilities and thus better adapt to the environment.

Conclusion

In fact, there is no need to pursue the continuation of infantile behavior. No matter how old we are, if we can always maintain the mentality of a child, be full of enthusiasm and curiosity about the world, then even if we are eighty years old, we can still celebrate Children's Day!