A restoration of the skeleton of Cacops by Samuel Wendell Williston, who named the genus in 1910. Cacops is a genus of dissorophid temnospondyl that is known from the Early Permian of the central United States. It was about 16 inches long and well adapted to a terrestrial lifestyle, with a heavily built skull, strong legs, a short tail, and a row of armor plates along its back. Compared to other dissorophids, it has an enormous otic notch in the back of the skull enclosed with a bony bar, indicating a large eardrum. Edwin Colbert suggests that perhaps it was a nocturnal animal like modern frogs. 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.