September 2014

Peeling off a layer

I recently had some good fortune to photograph some kind of gecko shedding its skin. What kind of gecko is it, and are those some sort of eye covers on the skin?

Answer

As the fine outer layer of skin peels off this Asian House Gecko, the transparent spectacles that covered its eyes can be clearly seen. Image courtesy of William Heidrich

The gecko is an introduced Asian House Gecko (Hemidactylus frenatus). Key identification features include the wavy edges to the vertical pupil, and indications of raised tubercles among the small granular scales on its back. Another important clue is the tail (not visible here) which has rings of prominent tubercles.

This lizard is shedding its skin. We humans also shed our skins, discarding and replacing individual cells on a daily basis. However, most reptiles discard their skin in one piece or in large sections, several times per year. Prior to shedding, a new layer forms underneath the outer layer of dead cells. A fluid separates the two layers and during this time the reptile is reclusive, appears dull and the eyes may be opaque. After a few days, the reptile begins rubbing its mouth and snout against rough objects. The old skin lifts back and peels off inside-out like the removal of a stocking. Some reptiles, including snakes and all Australian geckos, have no moveable eyelids. Their eyes are protected by a transparent spectacle resembling a contact lens. This is part of the skin. When the animal sheds, the spectacle is replaced too.

In addition to replacement lenses, geckos have another way of maintaining their acute vision. They use the tongue like a windscreen wiper to clean the surfaces of their lidless eyes.

Queensland Museum's Find out about... is proudly supported by the Thyne Reid Foundation and the Tim Fairfax Family Foundation.

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