Scientists report that snake embryos start life curled in a distinctive right-handed spiral and can explain the mechanics behind the twisting. The study finds that the embryo’s body grows faster than its gut, creating a length difference inside the egg. Because the tissues are effectively tethered, the elongating embryo buckles and twists into a spiral.
Researchers draw on observations from more than 900 embryos and use CT scans to reveal internal anatomy that shows how the coiling process develops. The work is framed as an advance in understanding a long-studied developmental pattern in snakes, with the coiling described as enabling embryos to package extensive body growth so that hatchlings emerge with long, elongated bodies compared with other vertebrates. While both accounts emphasize the same underlying growth-rate and mechanical explanation, they differ mainly in how they highlight the biological significance versus the specific developmental mechanism.
