The Deep-Sea Fish That Walks Sideways and Backwards
The News
Scientists sent a deep-sea robot into the South China Sea and filmed a strange fish called the armored searobin doing something no fish has ever been seen doing — walking on the ocean floor sideways and even backwards, using six little leg-like fin rays that stick out from its body.
Professor Pip crouched at the edge of a sunny tide pool and pulled a long brass magnifying glass from his coat pocket. His crooked spectacles slid down his snout as he peered into the water.
"Aha! There you are, little friend," he whispered.
Mia leaned in. "Professor Pip, what is that thing?"
Sitting on his outstretched paw was a small fish, no longer than a crayon, with wide feathery fins and — most peculiar of all — six delicate finger-like rays sticking out under its belly like tiny legs.
"This," said Pip, tail swishing, "is a cousin of the searobin. And scientists have just discovered that a searobin down in the deep sea can do something no other fish can do." He paused for dramatic effect. "It can walk. Sideways. AND backwards."
"Backwards?!" gasped Leo. "Fish don't have feet!"
"Precisely!" beamed Pip. "So how does it manage? Watch."
He set the little fish gently back into the tide pool, then patted his coat pockets and pulled out a small wooden crab puppet. He wiggled it across a flat rock — SCUTTLE, scuttle, scuttle — sideways.
"A crab walks like this because its legs bend to the side. Now what if a fish borrowed the same trick?" He flipped the crab and inched it slowly the other way — SCUTTLE, scuttle, scuttle — backwards.
The children giggled.
"Most fish only swim forward," Pip explained. "But the deep-sea searobin has grown special stiff fin rays that work like little rakes. It can PUSH itself in almost any direction — sideways like a crab, or backwards, using shrimp-style jerky hops. Scientists call this way of getting around locomotion. And when an animal invents a brand-new way to move, we call it a new adaptation."
"Oh!" said Mia. "Like when I learned to skip instead of just run!"
"Exactly right!" Pip clapped his paws.
He looked out toward the sea, where the tide was pulling back with a soft hush. "Somewhere far below those waves, in water so dark and heavy it would squeeze the breath out of a diver, a little fish is dancing sideways across the mud. And nobody knew until we sent a robot with a camera to look." His tail curled thoughtfully. "The ocean still has so many secrets, my friends. Now I wonder — what OTHER creatures have quietly invented ways of moving that we've never even imagined?"
Spark a Conversation
- Can you think of another animal that moves in a very unusual way? What does its body look like that helps it move that way?
- Why do you think we needed a robot to discover this fish's dance? What is it like at the bottom of the deep sea?
- If you could invent a brand-new way to move, what would it be?