Caught by the River

The Unexpected Truth About Animals

10th December 2017

An eel-centric extract from Lucy Cooke’s The Unexpected Truth About Animals, published by Doubleday and out now.

Genus Anguilla

There is no animal concerning whose origin and existence there is such a number of false beliefs and ridiculous fables.

Leopold Jacoby, ‘The Eel Question’, 1879



Aristotle was troubled by eels.

No matter how many the great Greek thinker sliced open, he could find no trace of their sex. Every other fish he’d examined on his island laboratory of Lesvos had easily detectable (and often quite delectable) eggs and conspicuous, albeit internal, testicles. But the eel appeared to be entirely sex-less. So, when Aristotle came to writing about them in his pioneering animal almanac in the fourth century bc, this most methodical of natural philoso- phers was forced to conclude that the eel ‘proceeds neither from pair, nor from an egg’ but was instead born of the ‘earth’s guts’, spontaneously emerging from mud; he thought the worm casts we see in wet sand were embryonic eels boiling out of the ground.

Aristotle was the first true scientist and the father of zoology. He made acute scientific observations about hundreds of crea- tures, but I am not surprised he was outfoxed by eels. These slippery characters keep their secrets especially well hidden. The idea that they emerge from the earth is fantastic, but no more so than the truth, since the so-called common freshwater eel, Anguilla anguilla, starts its life as an egg suspended in the depths of an underwater forest in the Sargasso Sea, the deepest, saltiest slice of the Atlantic. As a wisp of life no bigger than a grain of rice, it embarks on an odyssey lasting up to three years, to the rivers of Europe, during which it undergoes a transformation as radical as a mouse turning into a moose. It spends decades living in the mud and fattening itself up only so it can repeat the gruelling 6,000-kilometre journey back to its obscure oceanic womb, where it spawns in the shadowy recesses of the continental shelf and dies.

The fact that the eel only becomes sexually mature after its fourth, and final, metamorphosis at the very tail end of this par- ticularly peculiar life has helped to obscure its origins and bestowed it with a mythical status. Over the centuries, unravel- ling the mystery has pitted nations against each other, driven man to the remotest reaches of the seas and tormented some of the finest minds in the history of zoology, as everyone seemed to com- pete with one another to concoct the craziest theory to explain the eel’s genesis. No matter how outlandish, they couldn’t match the true story of the common freshwater eel, which is anything but ordinary: a remarkable tale of eel-starving Nazis, obsessive gonad hunters, gun-toting fishermen, the world’s most famous psycho- analyst – and me.


As a child, I, too, was rather obsessed with eels. When I was about seven my father sank an old Victorian bath in the garden, and con- verting this sterile tub for human ablution into the perfect pond ecosystem quickly became my principal pastime. I was a geeky child and I took this mission extremely seriously. Every Sunday my dad would accompany me to the ditches of Romney Marsh where I would spend happy hours trawling for any form of life with an improvised underwater animal trap he’d fashioned for me out of a pair of old net curtains. At the end of the day we’d return trium- phant, heady with the zeal of Victorian explorers, our underwater booty sloshing around in the back of his aged mini pickup, ready to be identified and introduced to my watery kingdom. The animals came two by two: marsh frogs, smooth newts, sticklebacks, whirli- gig beetles and pond skaters all joined the party in my bath. Alas no eels. My trusty net collected them, but attempting to transfer their slimy bodies into the bucket was like trying to hold onto water. Every time I grabbed one they’d escape, slithering off to safety overland – more like a snake than a fish out of water. They were elusive creatures and catching them became my Holy Grail.

What I didn’t know was that, if I had succeeded in my mission, the eels would have brought an end to my pleasant pond party by eating all the other guests.


The Unexpected Truth About Animals is out now, and is available to buy in the Caught by the River shop for the special price of £15.00. Get your copy here.

Lucy Cooke on Twitter