The Brachiosaurus lived about 156 to 145 million years ago, during what is known as the Jurassic Period. It lived on land, and was one of the tallest and largest dinosaurs whose fossils have been found. It had a long neck, small head, and thick tail that could whip away most attackers. The Brachiosaurus walked on four legs. Its very long neck gave the Brachiosaurus a giraffe-like stance and great height. These dinosaurs had large, powerful hearts and very high blood pressure, in order to pump blood up the long neck to the head and brain.

The Brachiosaurus was really huge- around 85 feet long and 40 to 50 feet tall. If it were alive today, it could peek into fourth story windows. Weighing 80 tons, or about as much as 12 elephants, it was a colossal dinosaur that had to feed constantly. The Brachiosaurus was an herbivore, a plant eater. It probably ate the tops of tall trees with its large teeth. It swallowed its food whole, without chewing it, digesting the plant material in its gut. Brachiosaurus probably travelled in herds and the herds may have migrated when they ate all the plants in the area. Their intelligence was the among the lowest of the dinosaurs.