Naria erosa, common name the gnawed or eroded cowry, is a species of sea snail, a cowry, a marine gastropod mollusk in the family Cypraeidae, the cowries.
The shell of these quite common cowries reaches on average 32- in length, with a maximum size of and a minimum adult size of . The dorsum is yellow-ocher or pale brown, with many small white spots. The extremities of the shell show dark brown spots. A dark brown area which is roughly rectangular is present on each side close to the edge. The base is white to light beige, with thin transverse stripes.
At night in the living cowries, the extremely papillose brownish mantle usually covers the shell completely, camouflaging the animal.
This species and its subspecies occur in the Indian Ocean along the coasts of Aldabra, Chagos, the Comores, the East Coast of South Africa, Kenya, Madagascar, the Mascarene Basin, Mauritius, Mozambique, Réunion, the Seychelles, Somalia and Tanzania, as well in the Western Pacific Ocean (Malaysia, Australia, Philippines, Polynesia and Hawaii).
These cowries live in warm tropical waters, on shallow intertidal reefs or in lagoons at about 2- of depth. Like most other cowries, during the day they usually hide under rocks slabs with the mantle drawn into the shell. They feed only at dawn or dusk.