Oligosoma moco

Moko skink

Oligosoma moco
(Duméril and Bibron, 1839)

Moko skink (Hauraki Gulf). <a href="https://www.instagram.com/nickharker.nz/">© Nick Harker</a>
Image attribution
Moko skink (Hauraki Gulf). © Nick Harker
Herpetofaunal category
NZ Skinks
Species complex
Conservation Status
At Risk - Relict
Previous scientific names
Leiolopisma moco
Common names
Moko skink,
Northern brown skink.

Length: SVL up to 81mm, with the tail being much longer than the body length

Weight: up to 8 grams

Description

A distinctively striped and notoriously bold skink from the northern North Island. Moko skinks are an alert species which are a conspicuous and abundant component of many pest-free islands, but have suffered greatly on the mainland with only a handful of populations now persisting.

Head has a short, blunt snout, and eyes which are large and strikingly dark. Dorsal colour varies from light grey-brown through to dark chocolate-brown and occasionally almost black, usually with a dark mid-dorsal stripe which may break up on the tail or continue in-tact. At the edges of the dorsum (back) are distinctive cream or light-tan coloured dorsolateral stripes, which run from the snout to the base of the tail. The flanks have dark-brown lateral stripes bordered above by the dorsolateral stripe and below by a lower-lateral stripe of the same or similar colour that also starts on the head running along the margin of the upper-jaw. Dorsal and lateral stripes may be bordered with black. Ventral surfaces are grey or pale cream / fawn. When in-tact, moko skinks have a distinctively long tapering tail which is often over one-and-a-half times their body length (SVL), and slightly prehensile to aid with climbing.

Life expectancy

Unknown.

Distribution

Occurs in the North Island, mainly on the east coast from the Bay of Plenty to Northland. Moko skinks are present (and often abundant) on many offshore islands, but have survived at only a small number of sites on the mainland. 

Ecology and habitat

Moko skinks are diurnal and strongly heliothermic, they can often be seen basking in full sun on the edges of tracks, open areas, or in forest clearings. They are mainly terrestrial but will often climb low trees / scrub to forage above ground, individuals have even been spotted over 3 metres above ground in cabbage trees (Cordyline australis), (Tim Harker personal communication, 2020). They usually occupy areas of coastal forest, scrub, and grassland, where they often take refuge under rocks and logs, or in dense vegetation such as rank grass, flax (Phormium spp) and Muehlenbeckia spp.

Social structure

Moko skinks are regarded as solitary, but often occur in high densities at pest-free sites.

Breeding biology

Female moko skinks breed annually producing litters of one to six young from February to March. Juveniles are independent from birth.

Diet

Moko skinks are omnivorous feeding on a wide range of small invertebrates, and the fruit / berries of native plants such as Kawakawa (Piper excelsum), Coprosma spp., and Muehlenbeckia spp.

Moko skinks have also been reported catching and consuming plague / rainbow skinks (Lampropholis delicata) (David Craddock personal communication, 2020). 

Disease

Unknown.

Conservation strategy

Moko skinks are secure on multiple pest free offshore islands. On the mainland, a population is protected / managed by a pest-proof fence and extensive predator control at Shakespear Open Sanctuary in northern Auckland.

Moko skinks have also been translocated to several additional pest-free islands including Matakohe / Limestone Island near Whanagrei (sourced from the Marotere Islands), and Rotoroa Island near Auckland (sourced from Tiritiri Matangi Island).

Interesting notes

Moko skinks get their common and scientific names from the Māori word for lizard ("moko").

Moko skinks have a deep divergence from other New Zealand skinks, and sit in their own clade on the Oligosoma phylogentic tree.

References

Chapple, D. G., Ritchie, P. A. & Daugherty, C. H. (2009). Origin, diversification, and systematics of the New Zealand skink fauna (Reptilia: Scincidae). Molecular Phylogenetics and Evolution, 52(2), 470-487.

Hitchmough, R.A., Barr, B., Lettink, M., Monks, J., Reardon, J., Tocher, M., van Winkel, D., Rolfe, J. (2016). Conservation status of New Zealand reptiles, 2015; New Zealand threat classification series 17. Wellington: New Zealand Department of Conservation.

Jewell, T. (2011). A photographic guide to reptiles and amphibians of New Zealand. Auckland: New Holland Publishing.

Robb, J. (1986). New Zealand Amphibians & Reptiles (Revised). Auckland: Collins, 128 pp.

van Winkel, D., Baling, M. & Hitchmough, R. (2018). Reptiles and Amphibians of New Zealand: A field guide. Auckland: Auckland University Press, 376 pp.