Think of something that really pisses you off, like really gets you going. Well, for fish-scale geckos in the genus Geckolepis, that one thing is being eaten. It just really puts a downer on their day. These little critters have developed a unique way of avoiding this annoyance, they shed their scales when attacked. And a newly described species in this family, Geckolepis megalepis, is the ultimate champion at this.
Fish-scale geckos scales are loosely attached, meaning that they can be torn off pretty easily. Some require a firm grip to detach them, but Geckolepis scales slip off at a mere touch. So when a predator bites down on them, they wriggle free and leave the hungry beast with only a mouthful of scales to chew on.
Now, it may seem a bit of a hassle to constantly be losing your protective layers (not to mention embarrassing to be running around a forest naked), but fish-scale geckos regrow a shiny new set of scales in only a few weeks. They are left without a single mark on them from their harrowing near-dinner experience. No unsightly scars for them.
The new species Geckolepis megalepis, which is endemic to Madagascar and the Comoro archipelago like all Geckolepis geckos, has the largest scales of them all. These tear off "with exceptional ease" according to the scientists who described it. They believe this is all down to the scales massive size and larger surface area, which can generate more friction than smaller scales.
The ease at which G. megalepis sheds itsscales make it the king of not getting eaten.
"What's really remarkable though is that these scales -- which are really dense and may be even be bony, and must be quite energetically costly to produce -- and the skin beneath them tear away with such ease, and can be regenerated quickly and without a scar," says Mark D. Scherz, who led the team that described G. megalepis.
As you can imagine, trying to catch something that is built not to be caught poses a few challenges. One gecko scientist caught them using cotton wool, lest they shed their scales all over the place before being dissected. Things get even more tricky as reptiles are generally identified by the patterns of their scales, but when Geckolepis loses their scales, the patterns can go as well. So the scientists turned to micro-CT's of the geckos (basically a 3-D x-ray). This allowed them to see how different G. megalepsis was from the others.
The scientists proposed that G. megalepsis be listed as Near Threatened under the IUCN Red List. It's found in a limestone karst area of Madagascar, within a range of around 182km2. Within its distribution area there is ongoing deforestation due to sapphire mining and livestock rearing.
Precisely how these geckos regenerate their scales is poorly understood. But a way to utilise this remarkable ability for our own sake is being looked into. Until the day that we too can regenerate like a gecko, we'll just have to make do with all those unsightly scars.