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Studies show that birds of prey have not hunted in packs



Restoration of Deinonychus

Artistic restoration of Deinonychus antirrhopus, Credit: Fred Wierum

Turns out, you really can’t believe everything you see in the movies.

A new analysis by the University of Wisconsin Oshchet on the teeth of rake birds published in a peer-reviewed journal Paleogeography, paleoclimatology, paleoecology it shows, that velociraptors and their kindred probably did not hunt in large, coordinated packs of dogs.

Birds of Prey (Deinonychus antirrhopus) with their sickle coupons became famous in the 1993 movie. jura parkwho portrayed them as highly intelligent, top predators who worked in large prey hunting groups.

“Raptor dinosaurs are often portrayed as wolf-like hunts,” says Joseph Frederickson, a vertebrate paleontologist and director of the Ways Earth Science Museum on the UWO Fox Cities campus. “However, the evidence for this behavior is not completely convincing. Since we cannot watch these dinosaurs hunt in person, we must use indirect methods to determine their behavior in life. “

Frederickson co-led the study in partnership with two colleagues from the University of Oklahoma and the Sam Noble Museum, Michael Engel and Richard Siffel.

Although widely accepted, evidence of the hunting of glittering dinosaurs suggested by the late celebrity Yale University paleontologist John Ostrom is relatively weak, Frederickson said.

“The problem with this idea is that living dinosaurs (birds) and their relatives (crocodiles) do not usually hunt in groups and rarely ever catch prey larger than themselves,” he explained.

“In addition, packing behavior is not fossilized, so we cannot directly test whether the animals actually worked together to prey.”

Recently, scientists have proposed a different model of behavior for birds of prey, thought to be more like Komodo dragons or crocodiles, in which individuals can attack the same animal, but cooperation is limited.

“We suggested in this study that there is a link between hunting for packs and the diet of animals as they grow,” says Frederickson.

In Komodo dragons, babies are at risk of being eaten by adults, so they find refuge in trees where they find a wealth of food inaccessible to their elderly parents living on earth. Animals that hunt in packs do not usually show this dietary diversity.

“If we can look at the diet of young birds of prey versus old birds of prey, we can hypothesize if they hunt in groups,” says Frederickson.

To do this, scientists have considered the chemistry of rake teeth Deinonychuswho lived in North America during the period limy A period of about 115 to 108 million years ago.

“Stable carbon and oxygen isotopes have been used to represent the diet and water sources for these animals. We also looked at a crocodile and a grazing dinosaur from the same geological formation, “he said.

Scientists have found that, like modern species, the Cretaceous crocodiles show a difference in diet between the smallest and largest teeth, showing a clear transition in the diet as they grow.

“This is what we would expect for an animal where parents do not provide food for their little ones,” says Frederickson. “We see the same pattern in birds of prey, where the smallest and the largest teeth do not have the same average carbon isotope values, indicating that they eat different foods. This means that young people have not been fed by adults, so we believe Jurassic Park was wrong with the robber’s behavior. “

Frederickson added that the method used in this study to analyze carbon in the teeth can be applied to see if other extinct creatures may have hunted in packs.

Reference: “Ontogenetic dietary changes Deinonychus antirrhopus (Theropoda; Dromaeosauridae): Insights into the Ecology and Social Behavior of Raptor Dinosaurs by Stable Isotope Analysis “by A. Frederickson, M. H. Engel, and R. L. Cifelli, May 3, 2020, Paleogeography, paleoclimatology, paleoecology,
DOI: 10.1016 / j.palaeo.2020.109780

Prior to joining UWO in July 2019, Frederickson was most recently an assistant professor at Southwestern Oklahoma State University. He was also the founder / manager of Oklahoma Educators Evolve!, An outreach and education organization that teaches science teachers in five states through field and museum geology experiences.




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