European Eel

ocean migration · endangered · shape-shifters

Epic ocean journey. European eels are born in the Sargasso Sea near the Caribbean, then drift across the Atlantic Ocean for years to reach European rivers where they grow up. When they're ready to have babies, they swim all the way back to where they were born, a journey of thousands of miles.

Five life stages. Scientists used to think the different stages of an eel's life were actually five different species because they look so unlike each other. Scientists now understand these stages as one animal that changes dramatically as it grows.

Mysterious spawning. No one has ever seen European eels mate in the wild, even though scientists have studied them for thousands of years. This makes the eel one of nature's best-kept secrets.

Critically endangered. Dams built for electricity block eels from swimming upstream to their nurseries, fishing catches too many baby eels before they grow up, and parasites make them sick. These problems together have made the European eel population shrink dramatically.