(Phys.org)—A team of researchers with members from the U.S., Portugal and France has conducted a study of the amount of energy required by the two main types of tortoises that reside on the Galapagos Islands—the domed and the saddleback—to flip themselves right side up when they overturn. In their paper published in Scientific Reports, the group describes analyzing shells of the two tortoise types, comparing them and then calculating which required more energy to flip itself back upright.