Ankylosaurus is the largest shelled dinosaur known to science, whose size is about an adult male African elephant. This lizard was all covered with dense, bony armor, consisting of individual plates, and the tail was crowned with menacing-looking club. Ankylosaurus was one of the largest representatives of its genus as it had a length of 6 to 8 meters and weighed from 5 to 8 tons.

This quadrupedal, with a broad, robust body had a wide, low skull, with two horns pointing backward from the back of the head, and two horns below these that pointed backward and down. The front part of the jaws was covered in a beak, with rows of small, leaf-shaped teeth farther behind it. Like other ornithischians, Ankylosaurus was herbivorous. Its wide muzzle was adapted to feed on low-growing crops, fibrous and woody plants. Though a number of scientists believes they may have had a varied diet, including tough leaves and pulpy fruits. Fossils of this dinosaur were found in 1906 by an expedition of the American Museum of Natural History in Montana, USA.