The Ankylosaurus  was a huge, armored dinosaur 25-35 feet long, 6 feet wide, 4 feet tall, and weighed between 3 – 4 tons.Ankylosaurs had a protective armor of bony plates. Unlike the armored nodosaurs, ankylosaurs had a large lump of bone at the ends of their trials, which they used as a hammer or club. One of the best-known ankylosaurs, from the preserved remains of about 40 individuals, is Euoplocephalus.