Glyptodon (grooved or carved tooth) was a large, armored mammal of the family Glyptodontidae, a relative of armadillos that lived during the Pleistocene Epoch. It was roughly the same size and weight as a Volkswagen, though flatter in shape. With its rounded, bony shell and squat limbs, it superficially resembled turtles, and the much earlier dinosaurian ankylosaur, as an example of the convergent evolution of unrelated lineages into similar forms. Glyptodon is believed to have been an herbivore, grazing on grasses and other plants found near rivers and small bodies of water. This animal appeared during Cenozoic era, the most recent era of geologic time, from about 65 million years ago to the present. The Cenozoic Era is characterized by the formation of modern continents and the diversification of mammals and plants. Grasses also evolved during the Cenozoic. The climate was warm and tropical toward the beginning of the era and cooled significantly in the second half, leading to several ice ages. Humans first appeared near the end of this era.