The Brachiosaurus is estimated to have had a life span of about 100 years. This estimate is based on body size, following the general rule that large animals live longer than smaller ones do.
The Brachiosaurus was a sauropod, or lizard-hipped dinosaur, first discovered in 1903 from fossils found in the Colorado River canyon. It was unusual because its forelegs were longer than its hind legs, giving the animal a steeply sloped back.
Scientists believe the Brachiosaurus browsed on high branches as a modern giraffe does and reached about 85 feet in length, being able to feed on branches as high as 30 feet. Estimates of its weight range from 31.6 to 48.4 tons.