Grand skink  (Oligosoma grande)

Classified as Vulnerable (VU) on the IUCN Red List (1).

As one of New Zealand’s largest and most impressive lizards, the grand skink justly deserves its name. Sadly though, it also shares the less fortunate title of being one of the nation’s rarest reptiles (2) (3). Most skinks have short-limbed, cylindrical bodies protected by a glossy armour of scales (4) (5), which, in the case of the grand skink, are black with yellowish flecks (2). This cryptic colouration provides excellent camouflage amongst the lichen covered rocks the grand skink inhabits (2).

The grand skink is confined to Otago in New Zealand (2) (3).

Inhabits schist rock outcrops surrounded by tussock grassland (3). The presence of deep crevices in the outcrops is essential to provide the skinks with protection from predators and extreme temperatures (3) (6).

Active during the day, especially during periods of sunshine, the grand skink is most commonly seen on rock surfaces, but will also travel up to 400 meters between outcrops, and will occasionally forage on nearby ground (3) (6). It is an omnivorous species with a diverse diet comprising a wide variety of invertebrates, fruit and vegetation (2) (3).

Becoming sexually mature at around four years of age, female grand skinks give birth to around two to four young each year. The annual survival rate is just less than 60 percent, but these skinks can live up to 17 years in the wild (3) (6).

The grand skink occupies a tiny proportion of its original range and faces the very real possibility of extinction within the next few years. The primary causes of its decline are thought to be habitat loss associated with human activities such as mining, forestry and agriculture, and predation by introduced mammals, including feral cats, stoats, weasels, ferrets and even hedgehogs (2) (3).

In 1995, a recovery plan was implemented to ensure the continued survival of wild populations of grand skink and otago skink, a similarly threatened species occupying an almost identical range (2) (6). As of early 2009, a replacement recovery plan, based on new information that has arisen since the start of the programme, is awaiting approval. The focus of the new recovery plan is to secure representative populations of the species in captivity; to establish which mammalian predators are having the greatest impact on the grand skink; and to raise public awareness of skink conservation. In addition, the New Zealand Department of Conservation has acquired substantial areas of land supporting existing populations of grand skink and is in the process of purchasing more suitable habitat (3).

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about the conservation of the grand skink see:

• New Zealand Department of Conservation:
  http://www.doc.govt.nz/upload/documents/getting-involved/consultations/closed-consultations/grand-otago-skink-recovery-plan-draft.pdf