The turtle and the dinosaur Though the soft-shelled turtle has a soft, leathery shell, all chelonians (turtles, tortoises and terrapins) show little variation in their basic structure.
烏龜，與鱉同屬於龜鱉目，除了鱉甲為肉質較柔軟，兩者外型與內部結構大同小異，今天生物學者認為烏龜是由二億五千萬年前石炭紀後期杯龍類恐龍演化而來。