Where Do Cowrie Shells Come From?
This Glossy Shell Is Made By a Sea Snail
Cowrie shells, with their glossy coat and toothed opening, are highly prized by collectors. However, few people know anything about the animal that once resided within. The most well known of these small sea snails is the Tiger Cowrie which has a mottled shell of brown, white and gray. Yet, there are roughly 200 different species of cowries, all of which are mollusks belonging to the family Cypraeidae.
Body Parts Aside From the Cowrie Shell
Cowries are more than just their shell. Neville Coleman describes the various parts of the cowrie in his article "Cowry Shells of the Indo-Pacific". Similar to most sea snails cowries also have a head with eyes and tentacles, they have a strong muscular foot used for crawling and they have internal organs protected by their shell. The tentacles are found on each side of its head and are used for sensing its environment. This animal also has a tongue-like ribbon called a radula used to scrape and eat algae. Some cowries eat corals, sponges, or other snails. The radula has about 200 rows of teeth and new teeth are grown as the old ones are worn away. However, the most interesting part of a cowrie is its shell.
The cowrie shell is secreted by a complex organ called the mantle. Unlike in other mollusks the cowrie mantle envelops the shell, thus creating the glossy surface. The mantle also varies from species to species with some being smooth and clear while others are covered in long papillae or pustules.
A Life History of the Cowrie Shell
Coleman further describes how most cowries live in inter-tidal zones, are nocturnal, and will emerge only at night to graze or hunt for prey. Cowries also have separate genders and reproduce through internal fertilization. The female lays her eggs and sits on them until they hatch, guarding them with her foot. A mollusk’s foot is a fleshy muscle on its underside also used for traveling. Once the eggs develop into larvae, they disperse through the water, drifting as plankton. Eventually the cowrie will settle and start to grow its shell. At first the animal will have a thin twisted shell but as it grows older the shell will round out and develop teeth. As an adult the animal’s shell will gain its distinctive luster. Then one day, two adult cowries will meet and the cycle will start over again. Some cowries can live up to 10 years while smaller ones live for 2 or 3 years.
Human Uses of Cowrie Shells
Cowrie shells have been popular for thousands of years. Dale Bennet's article in Fish 'n' Chips, a marine newsletter, describes a few of these uses. In Roman times, cowries were called “Porculi” or “little pigs”; Italians later called them “Porcello”. When Chinese pottery arrived in Europe in the seventeenth century it reminded people so much of cowrie shells, the new pottery was name “porcelain”. One species of this mollusk, Cypraea moneta was once used as money in the South Pacific. Cowries have also been used as currency in ancient China, India, and parts of Africa. Many cultures at some point in time also saw these shells as talismans that could help fertility. Obviously, they have also been used for decorative purposes.
Unfortunately, people’s love of the cowrie shell has pushed some species toward extinction. Instead of collecting them, it would be far better to admire them where they are or look at pictures of cowrie shells. The popular Tiger cowrie (Cypraea tigris) and the Gold-ringed cowrie (Cypraea annulus) are just two now on the endangered species list. Meanwhile, the Arabian cowrie (Cypraea arabica) is considered a vulnerable species in Singapore. Due to over-collecting these beautiful animals may not be enjoyed by future generations. Even shells that look empty are best left at the beach.
Cowrie Shells Come From Sea Snails
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