American researchers have found that large-bodied carnivorous dinosaurs, such as young dinosaurs, have replaced competing medium-sized species from the dinosaur communities.
The dinosaur communities were like a mall on a Saturday afternoon: full of teenagers
Said Kat Schroeder, Fellow at the University of New Mexico, lead a study published in the scientific journal Science.
They represented a large proportion of individuals of every kind and had a major influence on the resources available to societies.
Specialist added.
Although fossil remains are limited, it appears that dinosaurs were not distinctly diverse:
Only about 1500 species are known,
While the number of species of mammals and birds living today in the tens of thousands.
In the Mesozoic era, which began 252 million years ago and ended 66 million years ago, the number of large-bodied dinosaurs weighing one ton far exceeded those of less than 60 kg.
According to some researchers, even the strongest dinosaurs began life as “little cubs”, possibly needing various resources as they grow, and occupying ecosystems where smaller species would otherwise have thrived.
To test this theory, Schroeder and his colleagues analyzed data from fossil-rich sites in various parts of the world, including information on more than 550 species of dinosaurs, grouping the species according to their body size and whether they were carnivores or herbivores.
It has been found that in the dinosaur societies inhabited by giants – giant predators such as T. rexes – there are hardly any medium-sized carnivores.
There is a stark gap: miniscule carnivorous dinosaurs weighing between 100 and 1,000 kilograms lived in societies where mythropods were present.
Schroeder explained.
The reason for this gap appears to be the existence of gigantic teens, who start out in their lives as little puppy-sized objects and then become “tough teens” before reaching adulthood.
Experts’ conclusion is supported by the change in dinosaur diversity over time. There were smaller gaps in Jurassic societies, which began 200 million years ago and ended 145 million years ago, while they were actually larger in later Cretaceous societies.
This is because adolescent mythropods in the Jurassic period were roughly the size of adult specimens, and there were more herbivorous sauropods that could be killed. However, tyrannosaurs and applesaurs dominated the entire Cretaceous period, which varied greatly in size as they grew into adulthood.
