The gecko tails essentially stick to the body of the animals with adhesive forces, LiveScience reported.
"The tail contains 'score lines' at distinct horizontal fracture planes where the tail may be released as a response to predation," the authors wrote in the article.
"These scores penetrate all the way through the tissue where the structural integrity is maintained by adhesion forces," they said.
While scientists have long known that geckos - a nocturnal and often highly vocal lizard - and other amphibians shed their tails to evade predators (and then regenerate them later), exactly how they do this has been steeped in mystery.
One possibility was that the lizards had special fast-acting chemicals that essentially broke down connective tissue that held the tail on. But it wasn't clear how chemicals could do that so quickly.
To find out how the lizards lose their tails, the team used several types of microscopes to visualise the lizard tail's structure and also observed the appendage shedding in euthanized geckos.
They found the gecko tail had zigzag lines that separated segments of the tail, forming a "precut" line.
When the geckos shed their tail, they left behind a pointy, crown-shaped stump. At the stump, the team was able to see bizarre, mushroom-shaped structures.
Those structures, the team hypothesises, form to reduce the adhesive, or sticky, forces and allow the gecko tail to rip off.
Researchers also conducted a chemical analysis and found the lizards don't use enzymes to cut off their tails.
Instead, the gecko tail probably sticks on using adhesive forces, or the stickiness that occurs between two unlike molecules. That chemical "glue" would allow the lizards to quickly shed their tail without causing permanent damage.
Because geckos can regenerate their tails, it's a good strategy to evade a predator. Geckos already use mysterious adhesives for their sticky feet, so it's not all that surprising that sticky forces would play a role in other parts of their body, the authors wrote.
"The segmentation permits the release in an orchestrated manner, a design that facilitates the lizard's ability to shed its tail easy and quickly without employing a slow protease-based degradation of connective tissue," the researchers wrote.
The study was published in the journal PLoS One.
