Science deciphers the paradox of the lizard's tail for the first time

Scientists have discovered microscopic structures that allow lizards to cut off their own tails, but also to attach them firmly under normal conditions.

When faced with a choice between life and death, many animals are willing to sacrifice part of their body, such as spiders that can break their own legs, crabs that can break their claws and some rodents. They shed patches of their skin on their own. More interestingly, some species of sea slugs even cut off their own heads to remove the infected body part.

However, the image of a lizard cutting its own tail is still considered the highest "survival skill" in the animal world. Specifically, when meeting a predator, many lizards are ready to cut off their still wiggling tail before fleeing away.

This behavior confuses predators. In most cases, the remains of the lizard will become a "replacement doll", giving the cunning animal time to run away. Many species are even able to regenerate lost tails.

This extremely interesting self-defense mechanism seems to be too familiar, but in fact is still a mystery to scientists, when they cannot explain: "Why a lizard can lose their tails immediately, but under normal conditions they're still attached?"

The lizard's tail is firmly attached under normal conditions, but is easily broken when they are in danger.

Recently, Dr. Yong-Ak Song, a biomechanical engineer at New York University Abu Dhabi, has finally successfully explained the lizard's "tail paradox". He thinks that to do this, the lizard's tail must always be in a state of being simultaneously attached and detached. "They have to quickly separate their tails from their bodies to survive. But at the same time, they can't lose their tails too easily under normal conditions," Dr. Song shared.

To solve this problem, Dr. Song and colleagues examined the detached tails of geckos, geckos, and Schmidt desert lizards. after pulling them back with their hands.

Toàn bộ quá trình được ghi lại bằng camera với tốc độ 3000 khung hình/giây. Sau đó khi dùng kính hiển vi, nhóm nghiên cứu đã rất ngạc nhiên khi phát hiện ra rằng ở mỗi vết gãy - nơi phần đuôi tách ra khỏi cơ thể - đều có những cột trụ hình nấm với những lỗ chân lông nhỏ li ti.

Thay vì các phần của đuôi được đan vào nhau dọc theo mặt phẳng đứt gãy, các vi mô dày đặc trên mỗi đoạn dường như chỉ chạm nhẹ với nhau. Điều này làm cho đuôi thằn lằn giống như một "chòm sao giòn", với các đoạn nối lỏng lẻo. Nói cách khác, có thể hình dung rằng một phần đuôi của thằn lằn luôn được gắn "hờ" với cơ thể và chỉ đợi cơ hội để tách rời.

Ảnh chụp CT cho thấy những cột trụ hình nấm gồm những lỗ chân lông nhỏ li ti ở phần đuôi bị đứt gãy của thằn lằn đã tạo nên "liên kết hờ" với phần còn lại của cơ thể.

Although this microstructure can withstand a certain amount of force, the team found that they easily crumble when twisted, or suddenly pulled backwards.

According to Animangsu Ghatak, a chemical engineer at the Indian Institute of Technology Kanpur, the biology of lizard tails is reminiscent of the microstructure found on the adherent toes of geckos and tree frogs. .

The discovery of Dr. Song and colleagues published in the journal Science, as an illustration of how these tails strike the perfect balance between ruggedness and fragility.

The researchers believe that understanding the process that allows lizards to amputate their own tails could have applications in the areas of prosthetics, skin grafts or dressings. The same mechanism could even help the robot remove broken parts.