Why did the Brachiosaurus evolve to have a long neck?

One of the oldest ideas was that brachiopods were semi-aquatic. They needed a long neck to keep their heads out of the water. But that idea is no longer popular (The Debate between Brachiosaurus and Giraffatitan). read more

For Brachiosaurus, with its approximately 30-foot (9-meter) long neck, low browsing reduces the overall cost of foraging by 80 percent, compared with dinosaurs with shorter necks, according to their study in the journal Biology Letters. read more

Like all sauropod dinosaurs, Brachiosaurus was a quadrupedal animal with a small skull, a long neck, a large trunk with a high-ellipsoid cross section, a long, muscular tail and slender, columnar limbs. read more