Sometimes, the masterpieces of cinema that present scientific data make mistakes, more or less intentional, doing a disservice to the popularization of science. Many times because certain discoveries came after those films; others, due to lack of information; and others, such as licenses to grant more spectacularity to the audiovisual product. The cinema has not always represented science in a reliable way.
The 1993 hit movie Jurassic Park portrayed velociraptors as fast and highly intelligent predators, working in groups to hunt large prey. However, this representation does not seem to be consistent with what scientists know, for now, about the behavior of these dinosaurs.
A new University of Wisconsin Oshkosh analysis of velociraptor teeth, published in the peer-reviewed journal Palaeogeography, Palaeoclimatology, Palaeoecology shows that velociraptors and their relatives probably did not hunt in large groups, nor do they appear to know how to coordinate with each other , as movies show.
According to Joseph Frederickson, lead author of the study, vertebrate paleontologist and director of the Weis Museum of Earth Sciences on the UWO Fox Cities campus: “Predatory dinosaurs are often shown hunting in wolf-like packs. However, the evidence of this behavior is not entirely convincing ”.
So why are raptors often depicted hunting in a group?
The idea that velociraptors – long-tailed, large-clawed, carnivorous bipedal dinosaurs – hunted in packs was developed by John Ostrom, a famous paleontologist who revolutionized our knowledge of dinosaurs in the 1960s by reinforcing the idea that they resembled more, as a species, flightless birds than reptiles. Ostrom also postulated that the hunting behavior of the dinosaurs was, in effect, done in groups. But this scientific team believes that this idea of herd hunting is based on “weak foundations” , as expressed by the main author of the study, since there is no current evidence of the relatives of the dinosaurs that present a similar behavior.
“The problem with this idea is that the living descendants of dinosaurs (birds) and their relatives (crocodiles) do not usually hunt in groups and rarely hunt prey larger than themselves, ” explains Frederickson, in a statement issued by Phys .org.
But how do we know that velociraptors did not hunt in groups?
Estimating the behavior of extinct animals is a very complicated task. Since we cannot see these dinosaurs hunt live, scientists must use indirect methods to determine their behavior in life.
Researchers have proposed a different model of behavior in velociraptors, believed to be more like Komodo dragons or crocodiles: multiple individuals attack the same animal, but with limited cooperation.
In Komodo dragons, the young are at risk of being eaten by adults, so they take refuge in trees, where they find a large amount of food that is not available to their parents, who live on the ground. The key to this approach is that animals that hunt in packs generally do not display this dietary diversity.
Diet, an indicator of group hunting
“If we could have evidence of the diet of young raptors versus ancient raptors, we could hypothesize whether they actually hunted in groups,” says Frederickson.
To do this, the scientists analyzed the chemistry of the teeth of Deinonychus , which lived in North America during the Cretaceous period between 115 and 108 million years ago: “We use stable isotopes of carbon and oxygen to get an idea of diet and water sources of these animals. We also investigated a crocodile and a herbivorous dinosaur from the same geological formation. “
Thus, the scientists found that Cretaceous crocodiles, like modern species, show a difference in diet between the smallest and largest teeth, indicating different hunting behavior : “This is what we would expect from an animal where parents do not provide food for their young, ”says Frederickson. The researchers observed the same pattern, in addition, in raptors.
“These observations, which suggest that adults did not feed the young, are the reason why we believe that Jurassic Park was wrong about the behavior of velociraptors,” he says.
Dinosaurs, closer to birds than reptiles
In the collective imagination, dinosaurs are represented as beings similar to giant reptiles. But we must understand them as different species, similar to birds. In fact, today’s birds are considered to be descendants of the only type of dinosaur that survived the mass extinction 66 million years ago.
During the Homo Curiosus scientific dissemination event, the paleobiologist and omitologist Francisco Serrano explained it like this in his conference: “We have evidence that all modern birds come from ancient birds, which were terrestrial and granivorous (grain consumers)”.
In addition, he added: “Today we have enough evidence that they were covered in feathers .”
Referencia:
J.A. Frederickson et al, Ontogenetic dietary shifts in Deinonychus antirrhopus (Theropoda; Dromaeosauridae): Insights into the ecology and social behavior of raptorial dinosaurs through stable isotope analysis, Palaeogeography, Palaeoclimatology, Palaeoecology (2020). DOI: 10.1016/j.palaeo.2020.109780
