A dramatic illustration of how acceleration can change a body plan is seen in snakes. Where a typical vertebrate like a mouse has only around 60 vertebrae, snakes have between around 150 to 400, giving them extremely long spinal columns and enabling their sinuous locomotion. Snake embryos achieve this by accelerating their system for creating somites (body segments), which relies on an oscillator. The oscillator clock runs some four times faster in snake than in mouse embryos, initially creating very thin somites. These expand to adopt a typical vertebrate shape, elongating the body.