Mosasaurus, a formidable marine reptile of the Late Cretaceous period, dominated ancient oceans. This creature was not a dinosaur but belonged to a group of marine lizards related to modern-day monitor lizards and snakes. With a streamlined body, powerful flippers, and a large tail fluke, Mosasaurus was well-adapted for a fully aquatic existence and efficient hunting. Fossils found across nearly every continent indicate their widespread presence in the Late Cretaceous marine food web.
The Primary Prey
The diet of Mosasaurus primarily consisted of abundant marine life forms. Fish, including both bony fish and sharks, were staple components of their meals. These agile swimmers were plentiful in the Late Cretaceous seas, providing a consistent food source for the large marine reptiles. Another significant part of their diet included ammonites, which were shelled mollusks resembling modern-day nautilus. Some Mosasaurus species, such as Globidens, possessed specialized blunt, spherical teeth, suited for crushing the hard shells of these cephalopods and other mollusks.
Opportunistic Hunting and Varied Meals
Mosasaurus were opportunistic hunters, consuming a wide range of marine animals. Fossil evidence from stomach contents reveals a varied diet that included other marine reptiles, such as smaller mosasaurs, plesiosaurs, and sea turtles. Even ancient seabirds were not safe from these powerful predators. The double-hinged jaws of Mosasaurus, similar to those of snakes, allowed them to expand their mouths to swallow large prey items whole.
Clues from Fossil Evidence
Fossil Clues and Dental Morphology
Scientists have pieced together the diet of Mosasaurus through fossil evidence. Direct evidence comes from rare discoveries of preserved stomach contents, which contain remains of their last meals. These findings have revealed fragments of fish, cephalopods, and other marine reptiles within the digestive tracts of Mosasaurus specimens. Another clue comes from tooth marks found on the fossilized bones and shells of prey animals. Ammonite shells, for example, often bear impressions from Mosasaurus teeth.
The morphology of Mosasaurus teeth and jaws also provides insights into their feeding habits. Their robust jaws and the presence of a second set of teeth in the upper jaw indicate their capacity to hold and process large animals. Recent research employing 3D scanning techniques to analyze microscopic wear marks on fossilized teeth has also helped paleontologists understand the specific dietary preferences among different Mosasaurus species.