Diplodocus: Jurassic Sauropod

Diplodocus is one of the most commonly recognized dinosaurs, belonging to the sauropod family of herbivores. These giant dinosaurs lived during the late Jurassic Period and represent some of the largest animals ever to walk on the planet. Fossils of diplodocus have been unearthed in North America, especially in Montana, Colorado, Utah, and Wyoming.

Diplodocus was certainly one of the longest animals ever, reaching lengths of up to 90 feet. This puts it on par with even the longest marine creatures like the blue whale. Its neck along was 26 feet long and its long, whiplike tail was 45 feet long. Oddly enough, its head was very tiny, only about two feet in length. This would have meant that in order to meet its metabolic requirements, diplodocus would have needed to spend most of its waking hours eating vegetation. Constant eating would have been this animal's lot in life because it could only take a certain amount of food into its mouth at a time. Furthermore, this constant need for giant quantities of food is related to the nature of the dinosaur's teeth. The teeth of diplodocus were peglike and were used to strip leaves of plants like ferns off the stalk. They were incapable of chewing and instead probably used stones they had swallowed in order to grind up the vegetation in their digestive tract. This technique is used by many birds today, and is not as effective as grinding vegetation with teeth before it enters the digestive tract. Less efficient digestion means that the dinosaur would have needed more food to compensate. Diplodocus was light compared to other sauropods of comparable length, weighing only about 10-20 tons.

It was once thought that diplodocus and many other sauropods held their necks high off the ground in order to graze on treetops. However, diplodocus was unable to due this due to a couple of factors. First, its vertebrae would have needed extremely powerful tendons in order to rotate such a long neck to that height, and given the nature of the vertebrae in preserved finds, it seems unlikely they could rotate to that degree in the first place. In addition, the front legs were shorter than the hind legs which would have forced diplodocus into a more horizontal posture. Finally, it is unlikely that diplodocus had a heart powerful enough to force blood upwards through a 26 foot long channel in order to feed the animal's brain. It is estimated that the heart would need to weigh 1.6 tons in order to be powerful enough to force blood to the head placed upright. The length of the neck was probably adapted to allow diplodocus to poke its head in between trees in order to reach vegetation. It would not be able to move in forests due to the bulk of its body and the long neck would therefore be an advantageous adaptation for survival.

Diplodocus was not high on brain power, but it did not need to be. Once it attained a certain size, this titanic dinosaur could not be bothered by even the largest predators alive at the time in the Jurassic. Due to the fact that it did not face as many threats from predation, it is speculated that diplodocus could reach nearly 100 years in age. However, diplodocus and other titanic sauropods did not live past the Jurassic. As the climate became warmer and lush forests began to recede, sauropods became much smaller in the Cretaceous than their Jurassic relatives.