Researchers Uncover Evolutionary Origins of Crabs' Sideways Movement
A recent study has revealed that the distinctive sideways movement of true crabs, known as Brachyura, originated approximately 200 million years ago. This evolutionary trait was traced back to a shared ancestor from the Jurassic period, according to research published in eLife. The study involved the largest comparative analysis of crab locomotion to date, combining direct observations of living crabs with evolutionary data. Researchers filmed 50 species of true crabs to analyze their movement patterns, discovering that sideways walking likely evolved only once in a single ancestor. This movement style is believed to help crabs evade predators by allowing them to escape in unpredictable directions. The study highlights the ecological success of true crabs, which have diversified into various habitats worldwide. 
