"These 30-ton Apatosaurus are giant fortresses of flesh. However, they are too large to attack, even by fully grown Allosaurus."
—Allen, describing Apatosaurus

Apatosaurus ("Deceptive Lizard"), originally known as Brontosaurus (which means "Thunder Lizard"), is a genus of sauropod dinosaur which lived during the Late Jurassic Period in the United States of America. It belongs to the Diplodocidae Sauropods, obviously a relative of Diplodocus.



Apatosaurus lived during the Jurassic Period 155-145 million years ago. It shared the environment with other herbivores, including other sauropods, as well as Dryosaurus, Stegosaurus, and Allosaurus.


Apatosaurus was one of the largest sauruopds of the Jurassic and was also one of the largest dinosaurs the ever existed. They grew to a staggering 15-20 feet (4.5-6 meters) tall at the hips, measured 70-75 feet (21.3-22.8 meters) in length, and tipped the scales at 30 tons (60,000 lbs), 12 times heavier than an elephant.

30-ton sauropods of the Jurassic, Apatosaurus were prey for most predators. They are described as "giant fortresses of flesh", but were too large to any attack, even by the largest fully grown Allosaurus. Only the young, injured, sick or old were at risk of predation.


Like all sauropods and other kinds of herbivorous dinosaurs, Apatosaurus traveled in herds.