Meet the Earliest Known ‘Right-Handed’ Animal, a Worm-Like Creature That Lived About 550 Million Years Ago

During the Ediacaran period, the critter wriggled around on the ocean floor of what’s now South Australia and preferred to turn right, a fossil analysis suggests

Margherita Bassi | Daily Correspondent

July 14, 2026 10:00 a.m.

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A tiny critter that lived around 550 million years ago might represent the first known sign of right-handedness in animals—despite not having any hands.

The creature is a worm-like fossil animal called Spriggina floundersi, which is the state fossil of South Australia. Little is known about how the strange critter once lived, but new research has offered an intriguing clue. Spriggina probably favored turning to the right, suggesting an ancient start to a characteristic we humans experience every day, according to a study published July 9 in the journal Scientific Reports.

Spriggina had a flattened, segmented, oval-shaped body and was smaller than a thumb. It likely lived on or near the floor of a shallow ocean during the Ediacaran period, roughly 538 million to 635 million years ago. During this time frame, microscopic life evolved into multicellular organisms that could move, among other more complex behaviors. Additionally, Spriggina is one of the oldest known animals to feature bilateral symmetry, meaning it had mirrored left and right sides, as well as a clear front, back, top and bottom—a body plan seen in most modern-day animals.

“As soon as you get something that has a left and a right side, like Spriggina does, you start to see evidence of it preferring one side over the other,” study co-author Scott Evans, assistant curator of invertebrate paleontology at the American Museum of Natural History, tells the New York Times’ Jack Tamisiea.

Researchers haven’t been sure whether the critter could wriggle around in its environment or whether external forces, like ocean currents, pushed their bodies into the curved shapes seen in fossils. So, Evans and his colleagues investigated the shapes of more than 100 Spriggina specimens from Nilpena Ediacara National Park in South Australia and the South Australia Museum.

Measurements of the creatures’ curvature revealed that about twice as many had been bent in a right-turning direction when they died compared to the opposite direction. The trend suggests that Spriggina had a preferred direction of bodily movement, a trait known as laterality, which is commonly thought of as a sort of “handedness.”

“The presence of handedness in any kind of functional asymmetry, really deep into the fossil record, gives us important and interesting information about how these behaviors have evolved and how deeply in time they emerged,” Russell Bicknell, an evolutionary biologist at Flinders University in Australia who did not participate in the study, tells New Scientist’s James Woodford.

Additionally, Lidya Tarhan, a paleontologist at Yale University who was not involved in the study, tells the Times that the Spriggina fossils’ various shapes indicate that the creature could move on its own. If external forces had pushed their bodies, she adds, the specimens would probably all curve in the same way.

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Overall, the work hints that Spriggina may have had a complex nervous system and was more akin to animals alive today than once thought. Modern-day species that tend to favor one side of their bodies, like walruses, parrots and some frogs and lizards, also possess intricate abilities to perceive the world and move in response.

Spriggina’s laterality indicates that the ancient little creature already had a nervous system attached to muscles, allowing it to bend in a direction of its choosing, Diego García-Bellido, a paleontologist at Adelaide University in Australia who was not involved in the study, tells CNN’s Mindy Weisberger. “I am very cautious when interpreting the fossil record, and I believe Evans and co-authors have been as well,” he says. “They offer clear, valid arguments for their interpretations.”

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Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.