Jewelled Gecko

The jewelled gecko, Naultinus gemmeus, is a species of gecko endemic to the South Island of New Zealand. There are two main subgroups of jewelled geckos: those living in Otago and those living in Canterbury. One obvious difference is that some of the males of the Canterbury geckos are grey or brown with yellow, purple and white markings; whereas all Otago geckos are green with yellow and white markings. These and other NZ geckos are highly protected and it is illegal to capture or disturb them.

The average jewelled gecko is 160 mm long, including its tail that accounts for almost half of its overall length.  The jewelled gecko has long clawed toes that are adapted to climbing the trees and bushes they live in.

Unlike most reptiles, which are silent, the jewelled gecko uses “chirping and chattering communication calls and a loud croak of alarm or distress” (Gill & Whitaker, 1996).

A gecko can be distinguished from other lizards by looking at its skin and its head. A gecko’s skin appears lose and has a uniform granular texture, like a bucket of small beads. Its head will also be wider than the rest of its body, and it will have a defined neck. To differentiate the Naultinus geckos (commonly called green geckos) from Hoplodactylus geckos, New Zealand’s other gecko genus, note the time of day they are active. Green geckos are diurnal, which means they are active during the day, while Hoplodactylus geckos are nocturnal, or active at night. As the name suggests, green geckos are generally greener than Hoplodactylus geckos, but the dull coloured male jewelled gecko in Canterbury is a notable exception. If you find a green gecko on Banks Peninsula or the Otago Peninsula with splotches or stripes running down its back, it is most likely a jewelled gecko because other Naultinus geckos are much less decorated.

Jewelled geckos prefer forest trees less than 2 metres high. Their slender clawed toes allow them to climb branches with ease, and their markings help them hide very well amongst the leaves.

Jewelled geckos breed annually, mating in September and October and giving birth in May or June. Although gestation is usually eight to nine months, studies show that geckos can delay fertilization. Along with the New Caledonian rough-snouted gecko, New Zealand Geckos are the only geckos in the world to give birth to live young. Researchers hypothesize this is most likely due to the need to keep developing geckos warm in the cool climate. Gecko live-births aren’t exactly like mammalian live births; the baby geckos develop in the eggs which remain in the oviduct until they hatch prior to birth, known as ovoviviparity. Each litter usually consists of twin geckos, each nearly half the length of the mother at birth. The young generally remain with their parents, although no parental care is provided. Geckos generally reach sexual maturity after three years, although some studies believe that sexual maturity is a factor of size rather than age, and therefore is dependent on climate and food availability.

The exact lifespan of the jewelled gecko is unknown, but is believed to be surprisingly long for a creature its size. Other Naultinus geckos live upwards of 20 years in captivity, and many of New Zealand’s lizards live for 10–12 years in the wild.

Jewelled geckos are insectivores. They stalk flies, beetles, and other insects very slowly before suddenly lunging and capturing their prey with their mouths. A common misconception is that geckos catch prey with their tongues, but the tongue is merely used to hold down the prey after it has been caught in a gecko’s mouth. Geckos will also eat soft fruit and berries, but hardly ever eat dead insects.

Because they are ectothermic (cold-blooded) and diurnal (active during the daytime), jewelled geckos  regulate their body temperature by moving in and out of the shadows provided by the plants they live in. They are expert climbers, using their long, clawed toes and prehensile tail to get around. Their tail is strong enough to hang by, and geckos use it like another leg. Geckos can purposefully lose their tail if threatened as a means of defense, but because is so useful, they are less likely to drop it than other lizards are. The tail will regrow, but will never be as long as the original, nor have the same colour or patterning.

Jewelled geckos shed their skin every six to eight weeks during the summer. A gecko’s eyelids are always closed, but are transparent so that it can still see. When a gecko’s eyelids get dirty, it will lick them clean with its tongue.

Traditional Maori significance and uses

Although there are no mentions of the jewelled gecko in particular, we know that the Maori were aware of the little creatures, and many carvings seem to represent geckos. The Maoris believed geckos, particularly green geckos, to be bad omens. As Sir W. Buller reports in an early 20th century account:…this lizard, on being molested, emits a peculiar chattering sound, which the Maoris term laughing, and of which they have a wide-spread superstitious dread. The laugh of the green lizard was enough to terrify the bravest warrior, and its occult power for evil was strangely believed in by all the tribes in every part of the country. The reptile itself, whether dead or alive, was an object of universal fear among them...

Modern Used

Geckos are popular pets, and the jewelled gecko is certainly no exception. Because it is a threatened species, there is a lot of paperwork involved in owning one. Since 1981, permission must be obtained from the Department of Conservation (DoC) to possess a jewelled gecko, and the gecko itself must be acquired from an existing breeder, as it is illegal to remove one from its natural habitat. The DoC permit must be renewed every three years, and a cage inspection is part of the issuing and renewal procprocess. Records of births, deaths, and exchanges between breeders must also be kept. Nevertheless, they remain a pet that brings excitement and discovery to many intrigued owners.