 However, the size is variable across the islands and species; those from Pinzón Island are relatively small with a maximum known weight of and carapace length of approximately compared to range in tortoises from Santa Cruz Island.The tortoises' gigantism was probably a trait useful on continents that was fortuitously helpful for successful colonisation of these remote oceanic islands rather than an example of evolved insular gigantism.Large tortoises would have a greater chance of surviving the journey over water from the mainland as they can hold their heads a greater height above the water level and have a smaller surface area/volume ratio, which reduces osmotic water loss.