It’s bad enough to lose a tail, but getting eaten by a predator is considerably worse. Self-amputation, or the autonomy of a limb, is a prevalent defence tactic in the animal kingdom. While this is a beneficial biological trait in many cases, how can animals keep their detachable limbs from popping off at the slightest provocation?
Internally, the answer is found in a hierarchical structure.
“It needs to find the perfect amount of attachment so that it doesn’t fall off easily”. But it should also be able to be removed when necessary, according to Yong-Ak Song, a bioengineer at New York University. “It’s a delicate balancing act.”
A lizard’s tail must be able to cling to the lizard’s body tightly enough to prevent it from falling off due to small bumps and scratches. But it must also be able to drop off in an emergency. Micropillars, prongs, and nanopores make up the internal structure of a lizard tail, which work as a sequence of segments that clip into one other in rows, much like plugs do in sockets.
Any of these rows, known as fracture planes, can cause the tail to break off. This permits the lizard to choose how much of its tail to sacrifice in order to survive.
Scientists researched three different varieties of lizard tails to learn more about their internal anatomy. The team detached the limbs from the lizard bodies by gently tugging on the tails. The researchers next used a scanning electron microscope to examine the severed appendages, discovering that lizards’ nanopores aid tail adhesion by 1500 percent.
The Goldilocks concept applies to the prong-pillar-pore structure of lizards: it’s not too tight that the lizard can’t self-amputate, but not too loose that the tail falls off on its own.
This adaptation is necessary for lizards to survive. A lizard’s ability to sprint, jump, and mate are all slowed when it loses its tail… and endangering its ability to escape becoming the next meal for a predator.