In contrast, Naultinus are green (with the exceptions of males in two South Island species which exhibit sexual dimorphism in colouration), ovovivaparous, live up to 30 years or more and are strictly diurnal.

New Zealand has a temperate, maritime climate, and in terms of distribution Naultinus is one of the southernmost gecko genera in the world — some species live in habitats in the South Island which receive regular snowfall in winter.

The primary known agents of this catastrophic decline include predation by invasive mammalian and avian species, habitat destruction and poaching for the illegal pet trade.

[3] The broad fleshy tongue, which has a major function in cleaning the transparent scales which cover the eyes, is also brightly coloured; depending on the species it is red, orange, pink, yellow or black.

[10] All Naultinus species also possess very long, finely tapered, strongly prehensile tails which they use as a "fifth limb" for grasping when they climb among the twigs and leaves of their arboreal habitat.

[10] What was previously thought to be a distinct population of grayii, found only in the far north on the Aupōuri Peninsula has been determined from genetic work in the early 2000s to be a new species, more closely related, in fact, to elegans.

[10] South Island Naultinus were, in the past, placed in a separate genus called Heteropholis but this taxon was abandoned when new genetic research in the 1980s showed little phylogenetic basis for this taxonomic division.

[11] None of the Naultinus gecko populations are sympatric, presumably because each species is very finely adapted to its local environment and also because their respective ecological niches are incredibly similar.

[9] The Tuatara, a large, ground dwelling, generalist predator, will feed on native geckos, including Naultinus, where the two occur together on a few predator-free offshore islands.

[11] These mites, while essentially harmless, do suck small amounts of blood from their hosts, in time becoming quite swollen and taking on their characteristically vivid colouration as a result.

Because New Zealand has a temperate climate, Naultinus geckos live in areas which are at times (particularly in winter) exposed to very cold temperatures and high levels of rainfall.

In such adverse weather animals will descend from an arboreal position in vegetation and seek shelter on the ground in and around the base of these same plants or under rocks and other debris, where they are insulated to some degree against the cold air of the atmosphere.

The four species of North Island Naultinus exhibit, to varying degrees, defensive behaviours which involve "gaping" to reveal the vivid coloration of the interior of their mouthes - bright red in flavirictus and deep blue in grayi, elegans and punctatus -[2] and, in some cases, aggressive lunges and a strange sort of vocalization which has been described as a "barking sound".

[14] All four North Island Naultinus species will exhibit "gaping" behaviour when threatened but in addition grayi and punctatus will lunge aggressively at the potential predator in question, often barking as they do so.

[11] Gestation period in New Zealand geckos is variable but observations of animals in captivity suggest that it is usually a relatively long process, usually around 8–9 months -[9] similar to that of humans.

[9] These days, keepers must obtain their founder stock from an existing, licensed breeder and animals can only be given away or swapped; sale of any sort of native lizard commercially is illegal.

[9] DOC has in recent years begun sourcing Naultinus (particularly punctatus) for reintroductions to predator-free offshore islands from private collections, on the condition that the animals are in good health and of pure genetic origin (i.e.: they haven't hybridized with other species).

[16] Naultinus are also kept in captivity by enthusiasts in overseas countries but it should be stressed that trade is incredibly difficult, and one must obtain adequate CITES permits for importation and exportation.

[8] This is in stark contrast to anecdotal reports among NZ herpetoculturalists who found them abundant in suitable habitat (such as regenerating bush in the Marlborough Sounds) in the 1960s from which they have now all but vanished.

The three major factors thought to be responsible for this decline are; habitat destruction, predation by introduced mammalian species and poaching for the illegal pet trade.

[3] After the removal of mice from Mana Island in the '90s, lizard numbers increased massively – demonstrating that mouse predation does serious harm to native reptile populations.

[3] A unique population of Naultinus gemmeus near Hakatarema Pass, east of Twizel which displayed unusual colouration and a distinctive genetic profile was entirely destroyed when its forest habitat was cleared by a bulldozer for urban development.

[3] New Zealand's Naultinus are highly prized by international lizard collectors for three main reasons; firstly they have very attractive colouration and indeed, have been referred to by some as "the world's most beautiful geckos".

[19] There is a critical lack of scientific research that has been done on Naultinus species and this fact, combined with the behaviourally and visually cryptic nature of the genus pose major challenges to their conservation management.

[3] These "disappearing acts" have meant that the local extinction of many Naultinus populations has been overlooked because they were temporarily dismissed as simply being hard to find while sheltering from bad weather.

[3] Improved detection methods would allow scientists to monitor populations much more accurately and a number of different studies in recent years have been doing research into this area – some key ideas are a new type of cover mounted on trees for animals to hide in, pheremone lures and even terriers trained to pick up on the scent of native geckos.