New York, May 7 (IANS): It appears that famous movie on dinosaurs the 'Jurassic Park' may have got it all wrong as the Velociraptor dinosaurs did not hunt in packs, says a new study.
The raptors (Deinonychus antirrhopus) with their sickle-shaped talons were made famous in the 1993 blockbuster movie ‘Jurassic Park', which portrayed them as highly intelligent, apex predators that worked in groups to hunt large prey.
Now, a new analysis of raptor teeth, published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, shows that raptorial dinosaurs likely did not hunt in big, coordinated packs like dogs.
Recently, the scientists at the University of Wisconsin Oshkosh in the US has proposed a different model for behaviour in raptors that is thought to be more like Komodo dragons, in which individuals may attack the same animal but cooperation is limited.
"Raptorial dinosaurs often are shown as hunting in packs similar to wolves. The evidence for this behaviour, however, is not altogether convincing. Since we can't watch these dinosaurs hunt in person, we must use indirect methods to determine their behaviour in life," said study researcher Joseph Frederickson.
"Though widely accepted, evidence for the pack-hunting dinosaur proposed by the late famed Yale University paleontologist John Ostrom is relatively weak," Frederickson added.
"The problem with this idea is that living dinosaurs (birds) and their relatives (crocodilians) do not usually hunt in groups and rarely ever hunt prey larger than themselves," he explained.
Recently, the researchers have proposed a different model for behaviour in raptors that are thought to be more like Komodo dragons or crocodiles, in which individuals may attack the same animal but cooperation is limited.
"We proposed in this study that there is a correlation between pack hunting and the diet of animals as they grow," Frederickson said.
In Komodo dragons, babies are at risk of being eaten by adults, so they take refuge in trees, where they find a wealth of food unavailable to their larger ground-dwelling parents. Animals that hunt in packs do not generally show this dietary diversity.
"If we can look at the diet of young raptors versus old raptors, we can come up with a hypothesis for whether they hunted in groups," Frederickson said.
To do this, the research team considered the chemistry of teeth from the raptor Deinonychus, which lived in North America during the Cretaceous Period about 115 to 108 million years ago.
"Stable isotopes of carbon and oxygen were used to get an idea of diet and water sources for these animals. We also looked at a crocodilian and a herbivorous dinosaur from the same geologic formation," he said.
They found that the Cretaceous crocodilians, like modern species, show a difference in diet between the smallest and largest teeth, indicating a distinct transition in the diet as they grew.
"This is what we would expect for an animal where the parents do not provide food for their young," Frederickson said.
"We also see the same pattern in the raptors, where the smallest teeth and the large teeth do not have the same average carbon isotope values, indicating they were eating different foods," he added.
"This means the young were not being fed by the adults, which is why we believe Jurassic Park was wrong about raptor behaviour," the researcher noted.