Passage IV

NATURAL SCIENCE: This passage is adapted from the essay “Were Dinosaurs Dumb?” by Stephen Jay Gould (©1980 by Stephen Jay Gould).

The discovery of dinosaurs in the nineteenth century provided, or so it appeared, a quintessential case for the negative correlation of size and smarts. With their pea brains and giant bodies, dinosaurs became a symbol of lumbering stupidity, Their extinction seemed only to confirm their flawed design.Dinosaurs were not even granted the usual solace of a giant—great physical prowess....Dinosaurs ...have usually been reconstructed as slow and clumsy. In the standard illustration, Brontosaurus wades in a murky pond because he cannot hold up his own weight on land....Dinosaurs have been making a strong comeback of late, in this age of “I’m OK, You’re OK.” Most paleontologists are now willing to view them as energetic, active, and capable animals. The Brontosaurus that wallowed in its pond generation ago is now running on land, while pairs of males have been seen twining their necks about each other in elaborate sexual combat for access to females (much like the neck wrestling of giraffes). Modern anatomical reconstructions indicate strength and agility, and many paleontologists now believe that dinosaurs were warmblooded....The idea of warmblooded dinosaurs has captured the public imagination and received a torrent of press coverage. Yet another vindication of dinosaurian capability has received very little attention, although I regard it as equally significant, I refer to the issue of stupidity and its correlation with size. The revisionist interpretation, which I support, ... does not enshrine dinosaurs as paragons of intellect, but it does maintain that they were not small brain after all. They had the “right-sized ”brains for reptiles of their body size.I don’t wish to deny that flattened, minuscule head of large-bodied Stegosaurus houses little brain from our subjective, top-heavy perspective, but I do wish to assert that we should not expect more of beast. First of all, large animals have relatively smaller brains than related, small animals. The correlation of brain size with body size among kindred animals (all reptiles, all mammals for example) is remarkably regular. As we move from small to large animals, from mice to elephants or small lizards to Komodo dragons, brain size increases. But not so fast as body size. In other words, bodies grow faster than brains, and larger animals have low ratios of brain weight to body weight. In fact, brain grow only about two-thirds as fast as bodies. Since we have no reason to believe that large animals are consistently stupider than their smaller relatives, we must conclude that large animals require relatively less brain to do as well as smaller animals. If we do not recognize this relationship, we are likely to underestimate the mental power of very large animals, dinosaurs in particular....If behavioral complexity is one consequence of mental power ,then we might expect to uncover among dinosaurs some signs of social behavior that demand coordination, cohesiveness and recognition. Indeed we do, and it cannot be accidental that these signs were overlooked when dinosaurs labored under the burden of a falsely imposed obtuseness. Multiple trackways have been uncovered, with evidence for more than twenty animals traveling together in parallel movement. Did some dinosaurs live in herds? At the Davenport Ranch sauropod trackway, small footprints lie in the center and larger ones at the periphery. Could it be that some dinosaurs traveled much as some advanced herbivorous mammals do today, with large adults at the borders sheltering juveniles in the center?...But the best illustration of dinosaurian capability may well be the fact most often cited against them—their demise....The remarkable thing about dinosaurs is not that they became extinct, but that they dominated the earth for so long. Dinosaurs held away for 100 million years while mammals, all the while, lived as small animals in the interstices of their world. After 70 million years on top, we mammals have an excellent track record and good prospects for the future, but we have yet to display the staying power of dinosaurs.People, on this criterion, are scarcely worth mentioning—5 million years perhaps since Australopithecus, a mere 50,000 for our own species, Homo sapiens. Try the ultimate test within our system of values: Do you know anyone who would wager a substantial sum even at favorable odds on the proposition that Homo sapiens will last longer than Brontosaurus?