Madagascar Day Gecko

The vast majority of gecko species are nocturnal, with large fixed pupils that narrow to vertical slits in bright light to protect very light-sensitive eyes adapted for night vision. The genus Phelsuma, which includes the Madagascar day geckos, took a different evolutionary path — it re-evolved round pupils and cone-rich, colour-sensitive vision suited to daylight, allowing these geckos to bask, forage, and display in full sun rather than after dark. This shift likely opened up a whole daytime niche, including feeding on nectar-producing flowers that are open in daylight and basking to raise body temperature quickly in a way strictly nocturnal geckos cannot.

The underside of each toe carries rows of microscopic hair-like structures called setae, and each seta branches into hundreds of even smaller tips called spatulae. These structures come into such close contact with a surface that weak intermolecular attractions, known as van der Waals forces, build up across the enormous combined surface area of millions of spatulae, producing a strong, reversible grip without any glue or suction. This is the same basic mechanism used by other climbing geckos, and it works on smooth glass, polished stone, or a ceiling just as well as on bark, letting a day gecko walk upside down with no apparent effort.

Yes, and this is a well-documented and somewhat unusual ecological role for a lizard. Several Phelsuma day gecko species regularly visit nectar-producing flowers, pushing their heads in to lick nectar and inadvertently picking up pollen on their snout and head, which they then carry to the next flower they visit, effectively pollinating the plant in much the same way a bee or hummingbird would. On some islands, particularly smaller ones with few other nectar-feeding animals, day geckos are thought to be important or even essential pollinators for certain native plant species, making the loss of gecko populations a potential threat to those plants as well.

The skin of Phelsuma day geckos is thinner and more fragile than in many other geckos, and it detaches very readily where it is grabbed, tearing away in a patch rather than the gecko being held. This functions as an escape mechanism similar in principle to a lizard dropping its tail — a predator, or a person handling the gecko carelessly, is left holding a piece of skin while the gecko escapes with an open wound that scars over but does not regrow scales or colour in that spot. Because of this, day geckos should be handled minimally and never grabbed by the body; keepers who need to move one use a container rather than fingers.