NZ Skinks

Skinks belong to one of the most diverse lizard families, the Scincidae. There are a series of traits common to most species of skink: they typically have relatively small legs and no pronounced neck; long tails which they are able to self amputate (autotomy); ‘tight fitting’ smooth skin with flat, shiny, overlapping scales (geckos have ‘saggy’ skin and small granular scales). Skink can blink, unlike geckos which have a transparent scale in place of eyelids.

Skinks are highly alert animals, with an exceptional sense of smell, hearing, and sight. Skinks in general are good climbers, despite their relatively small limbs in comparison to the size of their body. The general rule of thumb with skinks is that the longer the toes the more arboreal (tree-dwelling) the species. Many species are also good swimmers.

As with geckos, skinks can self amputate their tails as an escape mechanism; a process called caudal autotomy. Skinks will shed their tail to escape the grasp of a predator, before attempting a getaway as the predator is distracted by the still wriggling detached tail. As the tail is a major fat storage organ for skinks, individuals may return to attempt to consume the dropped tail once the threat has passed.  The new tail is always shorter than the original and contains cartilage instead of bone, with the skin of a regenerating tail differing in texture and appearance from that of the original tail. In some cases, the new tail will grow back forked. Here’s a great video explaining autotomy.

Skinks are ectothermic, relying on environmental heat sources to generate energy. ‘Sunbathing’ is a common behaviour in our native skinks, either individually, or in the case of the Fiordland skink in communal groups of up to 30. All skinks shed their skin at intervals to accommodate growth, usually shed in small patches, unlike geckos which can shed their skin in one piece.

Skinks are the most frequently encountered reptile in New Zealand, often glimpsed in gardens running for cover. Skinks can be seen head bobbing and quivering their tails at each other when excited. New Zealand skink species vary in colour and size, with the longest (chevron skink) attaining a length of 350 mm (including tail). Some species are vocal, producing small squeak like noises. All but one species (the egg-laying skink, Oligosoma suteri) are ovoviviparous: a rare reproductive strategy whereby embryos develop inside eggs which are retained in the mother who then gives birth to live young. Skinks typically produce litters of between one and eight young. It can be very difficult to sex skinks (unless a female is gravid (carrying eggs or pregnant)).

New Zealand skinks are primarily carnivorous, consuming arthropods such as insects and spiders, many also eat soft fruit and will eat carrion (such as food regurgitated by seabirds) if the opportunity arises.

The Australian rainbow skink (Lampropholis delicata) is the only exotic lizard to have become established in New Zealand. Rainbow skinks are thriving and increasing in both numbers and range.

New Zealand skinks exhibit a high level of morphological conservatism (in simple terms, different species and subspecies can have very similar appearances), which can make the identification of species difficult. With the advent of DNA technology, genetic studies have focussed on resolving the phylogenetic (evolutionary) relationships of New Zealand’s skink taxa. All New Zealand skinks are now classified under the genus Oligosoma, we provide information on many species, making note of those species that were formerly classified under the genus Cyclodina and were affected by the taxonomic review.

For a more in-depth explanation of the taxonomic revision of New Zealand herpetofauna & current conservation classifications see:

• “Conservation status of New Zealand reptiles, 2012”
• “Dynamic taxonomy versus field identifcation: a dilema for New Zealand herpetologists”.

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