The Order Testudines includes turtles, tortoises, and terrapins—reptiles characterized by a bony or cartilaginous shell fused to the spine and ribs, providing protection. They are found worldwide in both aquatic and terrestrial habitats and are among the oldest reptile groups, dating back over 200 million years. Testudines are ectothermic, have no teeth (instead using sharp beaks), and show varied diets ranging from carnivory to strict herbivory. Most are long-lived and reproduce by laying shelled eggs on land. Ecologically, they play important roles as grazers, seed dispersers, and predators in their ecosystems.