The curious history of the goose barnacle

May 20, 2015, 12:04 p.m.

Which came first, the barnacle or the goose?

This species of filter-feeding crustacean is known as the goose barnacle. There is a species of goose known as the barnacle goose. They have similar names because it was once thought that one was born from the other.

The source of the old misunderstanding stems from the fact that humans didn't always know that birds migrate. People living in temperate Europe near barnacle geese never saw the birds lay eggs or raise chicks, so it was a mystery where they came from. Looking around, apparently some creative minds connected these barnacles with the birds.

Scienceblogs writes, "Around the end of the 12th century, Bishop Giraldus Cambrensis (Gerald of Wales) published a book Topographia Hiberniae, after King John’s successful invasion of parts of Ireland. In it, he described how Irish churchmen would eat the Barnacle Goose during fasts because 'these birds [are] not flesh nor being born of the flesh', for 'they are born at first like pieces of gum on logs of timber washed by the waves. Then enclosed in shells of a free form they hang by their beaks as if from the moss clinging to the wood and so at length in process of time obtaining a sure covering of feathers, they either dive off into the waters or fly away into free air. . . I have myself seen many times with my own eyes more than a thousand minute corpuscles of this kind of bird hanging to one log on the shore of the sea, enclosed in shells and already formed'. And so the myth was born, and spread around Europe."

It wasn't until several hundred years later that people realized that barnacle geese and goose barnacles weren't related in the slightest. Even with the mystery cleared up, the names of the two species are great reminders about how much we didn't know we didn't yet know about the natural world.

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Jaymi Heimbuch is a writer and photographer at Mother Nature Network. Follow her on Twitter, Google+ and Facebook.