Researchers explain why snake embryos coil into right-handed spirals
A team of scientists has identified the mechanical reason snake embryos form a right-handed coil, linking rapid body growth to a slower-growing gut.
An international research group led by Dr. Tetsuto Miyashita analyzed more than 900 snake embryos from 39 limbless squamate species, employing CT scans to uncover internal anatomy. They discovered a pillar-like gut segment that remains relatively short while the surrounding body lengthens rapidly, creating a mechanical constraint that buckles the embryo into a right-handed coil. The coiling occurs before muscular movement is possible, indicating a physical rather than active cause.
As development proceeds and the yolk shrinks, embryos gain space and muscle control, allowing some to unwind and coil leftward. The findings, published in Current Biology, provide a simple biomechanical model for spiral formation that may extend to other natural spirals. The project originated during the 2020 COVID lockdown, illustrating how a basic observational question can yield deep evolutionary insight.
Why it matters
Understanding the physical basis of snake embryo coiling sheds light on vertebrate development and spiral formation in nature.
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