It does not inhabit the mainland. Not because it cannot survive there. Because it evolved in isolation on the Chatham Islands, separated from New Zealand by eight hundred kilometres of ocean. The Chatham Island skink exists only on these remote islands, a product of geographic isolation and evolutionary divergence. Oligosoma nigriplantare nigriplantare inhabits coastal scrub and rocky outcrops on the Chatham Islands. It prefers exposed sites with salt spray, thriving where other reptiles cannot survive. Unlike mainland skinks, it has specialised scales that reduce water loss. Adults reach up to 12 centimetres in length, with a robust build adapted to harsh maritime conditions. Their large eyes provide excellent vision for hunting insects. Diet consists primarily of small insects and spiders. The skink hunts during the day when temperatures are warm. It also consumes nectar from native flowers when available. This omnivorous diet allows it to survive in arid environments, though it requires reliable insect populations to thrive. Breeding occurs in spring and summer, with females giving birth to one or two live young. Young are fully formed and independent at birth, fending for themselves from day one. This strategy maximises survival chances in a harsh environment. Classified as Nationally Critical, the Chatham Island skink faces an extremely uncertain future. Its distribution is extremely limited, confined to the Chatham Islands. Invasive species such as rats and cats threaten seedlings and adults. Habitat modification from historical human activity has reduced suitable coastal habitat. Each threat compounds the others. The Chatham Island skink has nowhere else to go. It is endemic to these islands. If it disappears here, it disappears everywhere. Conservation efforts focus on eradicating invasive predators and protecting remaining coastal habitat.