Apatosaurus

Apatosaurus is one of the most famous of the giant Jurassic plant-eaters. It was a huge, long-necked dinosaur, longer than two school buses and weighing as much as 7-13 elephants! If you look at older dinosaur books, you might not find Apatosaurus, but you will see "Brontosaurus". This was the name that was used for this dinosaur when the wrong head was mistakenly put on its body. For years an Apatosaurus body stood with the head of Camarasaurus on the end of its neck. This was named Brontosaurus and was one of the most popular dinosaurs for many years.

Apatosaurus is a fairly typical member of the diplodocid family - long neck, pillar like legs, long tapering tail and enormous size. It had, like the other family members, peg-like teeth in a head that seemed very small for such a large creature. Compared to Diplodocus, Apatosaurus has a shorter, thicker neck and a larger, heavier body. There is much speculation about how much these creatures needed to eat and how such a small head could ingest enough food to fuel such a large body. Some scientists have stated that these huge, small-headed creatures would have needed to eat every waking moment in order to provide enough food to keep such a large body alive. Apatosaurus seemed to have every adaptation needed for continuous eating, including having nostrils on the top of its head, so breathing would not interfere with eating.

In order to facilitate the processing of food, which it could not chew with its teeth. Apatosaurus probably swallowed stones that it kept in a gizzard similar to that found in a chicken. The tough plant fibers would spend time in the gizzard stewing and being ground up by the stones.

More real-life information: Apatosaurus at Wikipedia.

Appearance
An Apatosaurus holds a height of 9-12 meters (30-40 feet), length of 20-28 meters (90 feet), and weight of 18 tons.