Guardian: Aristotle thought the mysterious silver eel emerged from the earth fully formed. The young Sigmund Freud could not understand how it reproduced, and modern biologists puzzled for years over whether it ever returned to the Sargasso Sea, where it was known to breed.
Last year a team of Canadian scientists found conclusive proof of that extraordinary journey. They strapped tracking devices to 38 eels and followed as they migrated more than 900 miles at a depth of nearly a mile to the Sargasso, in...