Cobble skink facts for kids

Quick facts for kids Cobble skink
Conservation status
Nationally Critical (NZ TCS)
Scientific classification
Genus:	Oligosoma
Species:	aff. infrapunctatum "cobble"

The cobble skink (Oligosoma aff. infrapunctatum "cobble") is a special type of lizard. It belongs to the family called Scincidae. This skink is unique to New Zealand. It lives only on a small, stony beach at Granity, on the West Coast. In 2016, the cobble skink was very close to disappearing forever. Its numbers were dropping, and its home was in danger. Because of this, all known cobble skinks were caught and taken to Auckland Zoo for safety.

What is a Cobble Skink?

The cobble skink is part of a group known as the speckled skink family. Scientists first thought it was a different species just by looking at it. They noticed it had some unique features. Later, special genetic tests proved that it was indeed a distinct species. However, it still needs a formal scientific name.

What Does it Look Like?

Cobble skinks are small lizards. They are about 60–65 mm long from their nose to the start of their tail. They look quite similar to speckled skinks. Their backs are a medium brown color. They have a darker stripe down the middle, with lighter spots on the sides. Along their sides, they have dark brown stripes on a creamy background. These stripes also have lighter marks and flecks. Their bellies are a dull yellow, often with black spots. Cobble skinks are usually smaller than most speckled skinks. Their backs are also a more even brown color.

Where Do They Live?

At first, people thought this skink lived on a beach in northern Westland. They also thought it was found just north of the Grey River. But later surveys showed that cobble skinks live only on a short part of the coast at Granity. They literally live "behind the Granity Pub." They share this area with regular speckled skinks.

Cobble skinks make their homes deep within the cobblestones. These stones are just above the high-tide line. This is where a native plant called pohuehue (Muehlenbeckia complexa) meets the beach. This type of habitat was probably much more common along the West Coast a long time ago. This means cobble skinks were likely very abundant in the past.

Saving the Cobble Skink

When the cobble skink was first discovered, there were many of them. But they were hard to spot and rarely came out into the open. In 2015, scientists checked on them to get samples for genetic tests. They found that the skink's living area and numbers had shrunk a lot. More searches along the coast found no other groups of these skinks.

In late 2015, the cobble skink was listed as 'Nationally Critical'. This is the highest threat level in the New Zealand Threat Classification System. It meant they lived in an area smaller than one hectare (about the size of a sports field). By early 2016, there were only an estimated 30–40 cobble skinks left.

The number of cobble skinks has likely gone down because of animals brought in by humans. These include predators like stoats or rats. Their home is also threatened by introduced weeds. These weeds make the cobbles too stable. This stops storms from throwing new stones up the beach, which changes the natural habitat. The area is also losing land due to erosion. A report in January 2016 said the coastline at Granity was shrinking by 60–80 cm each year.

Because winter storms in 2016 could have destroyed their last home, the New Zealand Department of Conservation took action. They caught as many skinks as they could. The entire known population – possibly the whole species – was moved to Auckland Zoo. They will stay there until a safe coastal home can be found for them.