The Parasaurolophus is one of the most recognizable dinosaurs from the Late Cretaceous period, famed for the distinctive, backward-sweeping tube that extended from its skull. Living approximately 76 to 73 million years ago in what is now North America, this large creature captures the imagination of anyone interested in prehistoric life. Its unique physical structure often leads to questions about what it ate.
Classification and the Definitive Answer
Parasaurolophus was a herbivore, belonging to the Hadrosauridae group, commonly known as the “duck-billed” dinosaurs. The entire Hadrosauridae family consisted of plant-eaters, making them the dominant large herbivores of their time. Parasaurolophus was specifically a member of the Lambeosaurinae subfamily, defined by its hollow head crests. It likely consumed bulky, low-lying flora like pine needles, twigs, leaves, and tough ferns.
Anatomical Evidence of Herbivory
Evidence for the plant-based diet is found in the specialized structure of its mouth and jaws. Unlike carnivores, Parasaurolophus possessed a sophisticated chewing apparatus designed for processing fibrous material. Its mouth housed a “dental battery,” an arrangement of hundreds of small, diamond-shaped teeth packed together to form a single, massive grinding surface.
Only a few teeth within this battery were in use at any given time, but they were continually replaced from below, ensuring the surface remained sharp despite constant wear. This structure is analogous to the molars of modern grazing mammals, allowing for powerful chewing necessary to break down tough cellulose. The jaw joint facilitated a back-and-forth or side-to-side movement, enabling a true grinding motion that pulverized the vegetation.
The front of its mouth featured a broad, keratinous beak that lacked teeth altogether, similar to a duck’s bill. This beak was used to efficiently crop large amounts of vegetation from the ground or branches up to about 13 feet high. The collected plant matter was then moved into the cheeks, where the dental battery began the intensive mechanical processing required for digestion. This combination of a cropping beak and a self-sharpening grinding surface provides clear physical proof of its herbivorous lifestyle.
The Function of the Iconic Crest
While the teeth and jaws confirm the diet, the Parasaurolophus’s most distinctive feature, its long, hollow crest, had a function entirely separate from its feeding habits. This tube, formed by elongated nasal passages, swept upward and back from the skull. Early theories suggested uses like a snorkel or an air reservoir, but contemporary research points to roles in communication and display.
The crest contained a complex network of internal airways that acted as a resonating chamber, similar to a wind instrument. By forcing air through this convoluted passage, the animal could generate deep, low-frequency sounds. These low-pitched calls, perhaps like a foghorn or tuba, could travel long distances through the dense Cretaceous forests. This helped individuals maintain contact within herds or signal during mating displays.
The crest also served as an important visual display, likely used for species recognition and sexual selection within the herd. Different species of Parasaurolophus had distinct crest shapes. Variations in size may have distinguished between males and females. This prominent bony structure was a multifaceted organ for social signaling.