Seth Buddy of West Chop was shell-shocked.  

This exceptional birder and self-described amateur naturalist is always looking up and down for wonders of the natural world. Count on him to find birds and common and not-so-common creatures on his daily walks.  

Last week, Seth showed up at Felix Neck with a special find. He presented me with a beautiful purple cowrie shell and shared that he found it at a local beach. These shells are native to the Indo-Pacific and tropical regions of the world and it would be highly unlikely that one ended up on a Martha’s Vineyard beach.  

Unless, of course, it had help getting here. I suggested that it must have been brought and left by a person, not by the ocean’s tides and currents. He explained that he first saw one on a picnic table at the beach, then found another in the swash line of the surf. Still undeterred, he asked if it was possible that it got here on its own.  

Seth wasn’t convinced that it was a hitchhiker until he returned to the same beach the next day to find another, larger, exotic cowrie shell of a different variety on the same picnic table and agreed that indeed my hypothesis must be correct. Two rare shells found in the same place is too much of a coincidence.  

It is not surprising to find cowrie shells worldwide. They have been traded and shared and moved across the world throughout history.  Cowries were used as currency; for adornment on jewelry, clothes and in hair; and for mystical purposes, especially in Africa. Their tell-tale shape signified fertility and birth and portended wealth and good luck.    

Even today, cowries are valued for their shiny, colorful and patterned beauty. With more than 200 species with varying designs, they are collected and sold, so much so that malacologists — people who study mollusks — have concerns about overharvesting and the depletion of rare species. In one case, one exceptional shell sold for more than $50,000. 

Before these mollusks are brought into the trinket trade, cowrie or cowry (both spellings seem acceptable) shells were the homes of sea snails. In a bit of extroverted expansion, the snail’s mantle — the body wall that covers its internal organs — comes out of the shell and rests on the shell’s surface. The animal then secretes the shell layers on the top of the shell, rather than from the inside out. That is how the cowrie’s patterns and luminescent exterior are created. 

Many of the cowrie shells that we see for sale today have been etched or dipped in acid baths to bring out their interior colors or to make them even more shiny. Truth be told, they don’t need our efforts: they are stunners on their own.  

The sample found by Seth had potentially undergone some work, so to speak, to bring out its luminous purple color. That adaptation also made it difficult to identify its species, though together we believed it was either a tiger or snake-head cowrie. Both are members of the cypraea genus.  

Seth was not the only one to find a cowrie shell in Massachusetts recently. Two cowries were found at Boston archaeological digs and were believed to have been the property of enslaved people brought to this country. These shells share their owners’ story of displacement by their very existence and their value to the people that brought them.  

Cowries were believed to bring luck and wealth to those who possess them, so it is not surprising that folks carried them wherever they went. And whoever left those shells on a Vineyard beach sought to spread those sentiments. Seth has left the Island for the season and might have taken his cowrie shells with him — or left them for the next fortunate finder.   

Suzan Bellincampi is Islands director for Felix Neck Wildlife Sanctuary in Edgartown and the Nantucket Wildlife Sanctuaries. She is also the author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.