The smooth, green, dome-shaped snail of the rocky shore. The cat's eye has a thick, heavy shell that is a beautiful, polished green on the outside, often with darker, zigzag bands. The inside of the shell is a pearly, white-grey with a distinctive, dark brown, cat's-eye shaped operculum, the hard, plate-like door that the snail uses to seal itself into its shell. This is where the name comes from. These animals are the grazers of the intertidal rocks. They crawl slowly across the rocks at high tide, using their rasping, tongue-like radula to scrape algae off the surface. When the tide goes out, they seal themselves into their shells with that hard, cat's-eye operculum, holding in a few drops of water to keep their gills moist until the tide returns. They are the snails of the rock pool, the ones you see clinging to the rocks when exploring the shore at low tide. The life cycle of the cat's eye is slow and steady. They are broadcast spawners, releasing eggs and sperm into the water column where fertilisation occurs. The resulting larvae drift with the currents for weeks before settling onto a rocky surface and metamorphosing into tiny snails. Young cat's eyes are paler and lack the full pattern of their parents. They grow slowly, adding layers of shell material over years, the green colour deepening with age. A large, fully grown cat's eye may be decades old. Thick, hard shells protect them from waves and hungry oystercatchers. To see a cat's eye is to see a living jewel. A smooth, green, dome-shaped snail with a pearl inside, a treasure of the rocky shore. Not threatened, cat's eyes are common on rocky shores throughout the North Island and the northern South Island. Most common around Northland, Auckland, Coromandel and Bay of Plenty. The pūpū-tangata is the Māori name for the cat's eye snail, recognising its distinctive, eye-like operculum. The shells were used as jewellery and as the eyes for carved wooden figures, giving the carvings a lifelike, gleaming gaze. Today, the cat's eye is the snail of the rock pool, admired by children and collected for its beautiful, polished shell.