The secret structures behind lizards’ ability to either keep their tails or drop them and run have been uncovered in a new study. The research found that tiny mushroom-shaped structures were behind the magic trick, an insight that could inform some pretty nifty tech for the future.
The fascinating thing about lizard tails is that while they can be dropped at any moment, they are very firmly attached the rest of the time. Dropping a loosely connected limb wouldn’t be all that impressive, but how can such a strong bond break in an instant?
Using microscopy, researchers on a new paper published in the journal Science decided to find out. They took a closer look at the surfaces of broken tails along the “fracture plane”. They found that where each muscle breaks, there is a densely-packed layer of mushroom-shaped micropillars topped with a peppering of nanopores.
The team used emulation models to study how these structures can keep such a firm hold of tails before ditching them completely. They found that that the cleverly evolved mushroom micropillars were very adhesive under tension. However, all that could change with a slight twist.
After filming a tail breakage using a high-speed camera and slowing down the footage, they realized that the bending of the tail plays a crucial role in kicking off the tail drop. As the tail bends, a crack first appears on the bent side – and after that, it's swiftly tail go bye-bye.
The defense mechanism of self-amputating a limb (or sometimes your entire body, as in the case of some sea slugs) is known as autotomy. The physiological magic trick benefits lizards in that if they’re being hunted, they can ditch their tails which act as a distraction to predators because they can wiggle for some time after removal.
While humans for the most part don’t have a lot of use for dropping a leg at any given notice, understanding such a strong quick-release mechanism could have adhesion-related applications like improving skin grafts and wound healing. It could also give pivotal insights for soft robotics and 3D bioprinting.
“Autotomy proves to be a successful survival tool in the natural world, and its prevalence in both plants and animals gives confidence that it may be useful for scientific and engineering applications,” said study author Animangsu Ghatak in a statement.
“Particularly in robotics, stealth technology and prosthetics and for the safe operation of many critical installations, an optimized link similar to the one at present at the lizard tail can go a long way in protecting and expensive component or device from an unforeseen accident or mishap.”
Then again, having a quick-release tail could be kind of fun…