The Brontosaurus was a large, long-necked dinosaur that roamed the Earth during the Late Jurassic period, approximately 156 to 146 million years ago. It lived primarily in what is now the western United States, with many fossils found within the Morrison Formation. Brontosaurus could reach lengths of up to 21 to 23 meters (69 to 75 feet) and weigh between 15 to 20 tons.
Its Plant-Based Diet
The Brontosaurus maintained a plant-based diet, making it a herbivore. Its primary food sources included ferns, cycads, seed ferns, and horsetails, which were abundant during the Late Jurassic. It also consumed conifers and their tender shoots. Despite its massive size, the Brontosaurus was likely a nonselective browser, often feeding at ground level.
The environment it inhabited, particularly the Morrison Formation, was characterized as arid, suggesting that available vegetation might have been sparse. This necessitated efficient foraging strategies. The varied plant life of the Jurassic period provided the fibrous material to support such a large animal.
Eating Habits and Adaptations
Several adaptations facilitated its herbivorous lifestyle. Its long neck allowed it to reach high foliage, similar to modern giraffes, and sweep a wide area for food without moving its entire body. This increased “feeding envelope” helped conserve energy while foraging. Robust vertebrae in its neck, along with internal air sacs, reduced the overall weight of this lengthy structure.
Its teeth were peg-like or pencil-shaped, straight, thin, and pointed. These teeth were not suited for chewing or grinding food, but rather for stripping leaves from branches or raking vegetation. Its teeth were homodont, meaning they were all similar in shape and replaced frequently.
Since the Brontosaurus did not chew its food, digestion relied on other mechanisms. It would swallow stones, known as gastroliths, which aided in grinding the plant material within its large stomach or gut. A diverse community of gut microbes would then break down the vast quantities of fibrous plant matter. Maintaining its enormous body size required continuous eating, with daily energy needs estimated to be between 200,000 and 500,000 kilojoules. Sauropods, including Brontosaurus, are thought to have had high metabolic rates, comparable to those of modern birds, suggesting they were warm-blooded animals.