The Brachiosaurus most likely defended itself by simply smashing predators with its tail or feet because it had no other way to defend itself. Because the Brachiosaurus was so large, however, it is likely that predators simply hunted smaller prey.
A Brachiosaurus weighed between 60,000 and 170,000 pounds. This weight places it among the heaviest dinosaurs ever discovered. Because of this huge size, it may have been difficult prey for even large predators although it may have been one of the least intelligent dinosaurs to ever live.
To sustain this mass, a Brachiosaurus would have had to eat up to 400 pounds of food each day. Its neck was also so long that the dinosaur may not have been able to keep it in the air for very long because its heart may have been unable to pump blood to such heights.
The species lived in the Jurassic period from around 145 to 155 million years ago. Brachiosaurus fossils have been found in both Africa and North America. Due to the animal's size, it was speculated that it spent much of its time underwater. If submerged, however, the weight of the water is likely to have crushed a Brachiosaurus , so it is very likely that it lived on land.