Despite their reputation as strictly herbivores, some giant dinosaurs ate crustaceans as well. This is reported in a new paleontological study, the results of which are published in the journal Scientific Reports. Scientists have found pieces of crustacean shells in fossilized dinosaur feces.
“We don't deny that these dinosaurs were herbivores, but the dinosaur diet was more varied than is commonly believed,” said Karen Chin, co-author of the study and curator of the paleontology department at the University of Colorado Museum of Natural History at Boulder.
Most dinosaurs seemed to have varied diets. The chewing teeth and wide jaws of the fossils found indicate that ancient dinosaurs ate foliage. At the same time, bite marks on the bones of other animals also indicate predatory tendencies. The body structure of dinosaurs allowed them to feed on foliage at a fairly high level - about the level of a giraffe. But still, there is very little valuable data on the diet of dinosaurs, since fossilized remains of the contents of the stomach of these animals are extremely rare.
To fill gaps in knowledge, paleontologists have compared herbivorous dinosaurs to today's large herbivores - elephants and hippos. Elephants feed only on fruits and grass, hippos have also long been considered exclusively herbivores. However, in 2015, during a study of one population of hippos in Zambia, it turned out that these giants do not disdain kangaroos, flamingos and other birds and smaller animals.
Karen Chin calls fossilized dinosaur excreta with a special term - coprolites. In Utah, Chin found both small coprolites and the remains of a "public latrine," a large collection of coprolites too large for one animal. In Montana, the volume of some coprolites was seven liters - the volume of one elephant feces.
Once Chin discovered pieces of wood in coprolites. The scientist suggested that dinosaurs could mistakenly bite the bark of trees, trying to get leaves or nuts, because wood is not very nutritious. However, there was too much wood in the coprolites: then Chin suggested that dinosaurs ate soft rotten wood. Chin continued her search for rotten wood in dinosaur coprolites, but came across something more interesting. At first, Chn assumed it was an eggshell. During the analysis of coprolites, it turned out that the unusual particles are not shells, but pieces of crustacean shells. It is impossible to say exactly what kind of animals they were. Perhaps, terrestrial analogs of modern lobsters or sea crabs, only larger.
Why herbivorous dinosaurs suddenly chose crustaceans is unclear. Karen Chin suggested three versions. According to the first, dinosaurs were indeed very stupid and illegible creatures. The second version, on the contrary, assumes a high selectivity of dinosaurs. The third and most likely version is more complex: it is likely that crustaceans lived in rotten trees in the pastures of dinosaurs. In doing so, Chin rules out the possibility that dinosaurs swallowed crustaceans by accident. The size of crustaceans was equal to 20-60 percent of the size of the mouth of dinosaurs, it is impossible to swallow it by mistake. As one explanation, Chin suggested that dinosaurs hunted crustaceans during their breeding season. Herbivorous birds include more calcium in their diet before laying eggs.