How the Brain Limited the Size of Dinosaurs

Long-necked Sauropods, like Brontosaurus, were the largest animals on earth, but their brain, not their leg strength, is what kept them from getting any bigger. With their heads soaring 60 feet above the ground, Sauropods were gigantic animals, about the same height and length of The White House. Imagine the tremendous bone strength and muscle force required to support their 65 ton mass, equivalent to the crushing weight of a stack of 30-40 automobiles. The necks of long-necked Sauropods were 30 to 40 feet long (10-12 m), the length of the extended arm of the Statue of Liberty bearing the torch (42 feet). A massive heart would have been required to produce the 700 mm Hg pressure needed to pump blood to the Sauropod's head; the same pressure that is exerted on your body by diving in the ocean to a depth of 30 feet (10 m). It has been calculated that the left ventricle of the dinosaur's heart would have to weigh 2 metric tons to pump blood that high. That is 15 times heaver than the left ventricle of whales. Such an enormous heart muscle would have consumed 64% of the dinosaur's energy (basal metabolism), leaving the creature little energy for everything else. To overcome the problem of pumping blood to their brain, Sauropods may have been aquatic, but this outdated view is no longer accepted. Alternatively, Sauropods may have slinked around on land with their heads held low, grazing on grass with their noses in the turf, but if they raised their heads at the soun...
Source: Science - The Huffington Post - Category: Science Source Type: news