Hungry teenage dinosaurs outdid their competitors

Any parent of a growing teen knows their appetite can reach colossal proportions. Now imagine you had a guy King Tirano of Soris Check the refrigerator. The The dinosaurs’ massive appetite led to the re-formation of food chains Into their environment and drive out other carnivores, according to a new study published today in SciencesFrom hundreds of dinosaurs of all sizes.

“The elegant study puts real numbers on something we’ve been suspicious of for some time,” says Steve Brussat, a paleontologist at the University of Edinburgh who was not involved in the study. There were not many medium-sized carnivores “because the young, adolescents, and adults of the great feral dinosaurs were accumulating these niches.”

Most animal groups contain many small species, slightly fewer intermediate species, and even fewer large species. In contrast, extinct dinosaurs, especially carnivores, had many species not larger than today’s chickens and also many gigantic species, but few of them are medium in size.

Paleontologists have questioned whether small dinosaurs outnumbered average-sized adults when exploring the habitats and food sources these species may have eaten. To test the idea, Caitlin Schroeder, a doctoral student at the University of New Mexico (UNM), Albuquerque, investigated a global set of fossil data called the Palaeontology Database to determine the size distribution of more than 550 dinosaur species in 43 ancient ecosystems. More than 136 million years old and seven continents.

In most societies, herbivorous dinosaurs come in various sizes. But, he says, “carnivores are completely different.” Carnivores weighing 100-1000 kg have always been very rare. “It’s like you go to the savannah and see nothing the size of a fox and a lion,” Schroeder says. The patterns in all of the dinosaur societies studied, he says, are “very similar, which is not what you’d expect from societies separated by 100 million and a half years from the globe.” “They did it on a large scale,” says Gregory Erickson, a paleontologist at Florida State University. “It’s impressive and very complete … we saw the gap [in species’ sizes] For years, however, it has not been identified. “

To explore why, Schroeder and paleontologists Felisa Smith of UNM and Kathleen Lyons of the University of Nebraska in Lincoln modeled the role of juvenile carnivores such as Tyrannosaurus Rex It may have played in ecosystems, based on their growth curves and the relative number of young and old found in the “mass death” fossil family. “We said, well, if guys really use this space, how much do you expect them to?” Smith says. His calculations showed that “teenagers are filling the void,” he said. “If you fill it out, you will have a community like what you expected.”

The effect may be stronger in carnivores because each type of carnivorous dinosaur has occupied a wide range of niches. They hatch from relatively young eggs. Even the largest only weighed about 15 kilograms when they were dogs. So they have grown up very quickly, changing diets and hunting techniques to suit their new sizes and competing with a variety of other species along the way, says Erickson.

Mike Benton, a paleontologist at the University of Bristol, says the study’s focus on how animals change their ports as they grow offers new insights. “It will make people see the interactions between predator and prey differently.”