Scientists have discovered microscopic structures that allow lizards to voluntarily shed their tails, yet also enable them to remain firmly attached under normal conditions.
When faced with the choice between life and death, many animals are willing to sacrifice part of their bodies, such as spiders that can break their own legs, crabs that can detach their claws, and some small rodents that can shed patches of their skin. Interestingly, some sea slugs can even decapitate themselves to eliminate infected parts of their bodies.
However, the image of a lizard voluntarily shedding its tail is considered the pinnacle of “survival skills” in the animal kingdom. Specifically, when confronted by a predator, many lizards are ready to detach their still-wiggling tails before fleeing.
This behavior confuses the predator. In most cases, the remaining part of the lizard becomes a “decoy”, giving the clever creature time to escape. Many species can even regenerate lost tails.
This fascinating self-defense mechanism may seem familiar, but it remains a mystery for scientists, who have yet to explain: “Why can a lizard lose its tail instantly, yet remain firmly attached under normal conditions?”
Lizard tail firmly attached under normal conditions but easily detached when threatened.
Recently, Dr. Yong-Ak Song, a biomechanical engineer at New York University Abu Dhabi, successfully explained the “tail paradox” of lizards. He believes that for this to happen, the lizard’s tail must always be in a state of being both firmly attached and easily separable. “They must quickly detach their tail from their body to survive. However, at the same time, it cannot lose its tail too easily under normal conditions,” Dr. Song shared.
To solve this puzzle, Dr. Song and his colleagues examined the tails of geckos, chameleons, and Schmidt’s desert lizards after manually pulling these tails backward.
The entire process was recorded using a camera at 3000 frames per second. Upon using a microscope, the research team was surprised to discover that at each fracture point, where the tail detaches from the body, there are mushroom-shaped pillars with tiny pores.
Instead of the tail parts interlocking along the fracture plane, the dense microscale structures on each segment seem to barely touch each other. This makes the lizard’s tail resemble a “brittle constellation”, with loosely connected segments. In other words, it can be imagined that part of the lizard’s tail is always “loosely” attached to the body, just waiting for the opportunity to separate.
CT scan reveals mushroom-shaped pillars with tiny pores in the fractured tail of the lizard, creating a “loose connection” with the rest of the body.
Although this microscopic structure can withstand a certain force, the research team found that they easily shatter when twisted or suddenly pulled backward.
According to Animangsu Ghatak, a chemical engineer at the Indian Institute of Technology Kanpur, the biological mechanism of lizard tails is reminiscent of the microscopic structures found on the sticky toes of geckos and tree frogs.
The findings of Dr. Song and his colleagues were published in the journal Science, illustrating how these tails have achieved a perfect balance between firmness and fragility.
The researchers believe that understanding the process that allows lizards to shed their tails could have applications in prosthetics, skin grafting, or bandaging. Even, similar mechanisms could help robots remove damaged parts.
