How did tortoise get its shell?

The tortoise's shell evolved over millions of years as a protective adaptation against predators and environmental challenges. Initially, the shell likely developed from the expansion of ribs and a fusion of bones in the tortoise's back, providing a hard, bony structure. This unique feature not only serves as armor but also plays a role in thermoregulation and buoyancy in some aquatic species. Through natural selection, those tortoises with shells had a better chance of survival and reproduction, leading to the species we see today.