<h1 class="pgc-h-arrow-right" > why weren't there huge mammals in the age of the dinosaurs? </h1>
In the age of dinosaurs, mammals were a weak group that had long been oppressed by dinosaurs.
Throughout the Mesozoic Era, when dinosaurs lived, mammals were small, mostly about the size of today's mice and weasels. The earliest euphrasia appeared 160 million years ago in the late Jurassic period, and was found in Liaoning Province, China, which is known as the Juramaia sinensis. This animal is only 10 cm long and usually lives in trees and feeds on insects.
Image note: A restored image of the Jurassic beast, the picture comes from the network
Since the emergence of the Chinese Jurassic, the variety of mammals has been increasing, and the range of survival has expanded to illuminate the whole world, but there has been no qualitative leap in body size, all of which are rat-sized animals.
Image note: A jurassic beast that was hunted by a near-bird dragon, picture from the Internet
The largest known Mesozoic mammal was also found in western Liaoning, China, as reptiles (Repenomamus), which lived 125 million years ago. The reptile is larger, more than 1 meter long, weighs about 15 kilograms, and is about the size of a dog.
Reptiles are cunning carnivores with sharp canine teeth in their mouths that can be used to bite prey to death. Paleontologists have found juvenile psittaciosaur fossils in the stomachs of reptiles that have not yet been fully digested, proving that reptiles once captured juvenile psittaciosaurs, and it has become the only mammal that once fed on dinosaurs.
Image note: Fossils of reptiles, picture from the web
Caption: Reptiles attacking and killing dinosaurs, image from the web
Reptiles are really the peak of mammals in the Mesozoic era, and none of the mammals we have found in the Mesozoic age have surpassed the size of reptiles.
Why, in the age of the dinosaurs, mammals were not larger, and breeds comparable to lions, tigers and even elephants appeared?
The reason is simple, because of the presence of dinosaurs. Dinosaurs, as the most dominant terrestrial vertebrates at that time, had occupied the terrestrial ecosystem, completely suppressing the newborn mammals, and simply did not give mammals the possibility and space to be large.
Image note: Mammals hunted by dinosaurs, image from the Internet
In fact, if you trace the time when dinosaurs first appeared, they were also very small. In the late Triassic period, the land was dominated by the famous suborder Lloyd's crocodile, a large and ferocious reptile that occupied the position of landing raw carnivores, and they also suppressed dinosaurs for a long time, making dinosaurs unable to be large. It was not until after the Triassic-Jurassic extinction event, with the extinction of the suborder Lloyd's crocodile, that the dinosaurs were given the opportunity to grow larger and stronger.
Picture note: The Post crocodile belongs to the suborder Of the Lloyd's crocodile, the picture is from the Internet
Image note: In North America in the Triassic Period, when the dinosaurs had not yet risen, the picture came from the Internet
The larger size of mammals also benefited from the Cretaceous-Paleogene extinction event. With the extinction of dinosaurs (non-avian dinosaurs), mammals gradually became larger, but unlike what we usually think: mammals remained small for more than 10 million years after the extinction of dinosaurs. For example, the Messer Rainforest in the restored picture below represents Germany in the Eocene 47 million years ago, when mammals still did not exceed 100 kilograms.
Photo note: A tropical rainforest by Raul Martin during the Eocene period in Messel, Germany
It wasn't until 4,000 years ago that mammals began to truly scale up, with the emergence of large mammals such as thunder beasts, giant rhinocerosses, and Ahn's middle beasts.
The giant rhinoceros is one of the largest mammals in history, and the image comes from the Internet
A newborn animal phyla needs to flourish and scale up the corresponding niches, and the conceding of such niches often requires events such as mass extinctions to be provided. In a stable ecological environment, due to the saturation of ecological niches, new species are often squeezed and unable to be large-scaled and achieve rich diversity, but recent studies have shown that mammals have reached an "explosion of diversity" in the Jurassic Period.
Image / Network (Intrusion and Deletion)
Text / Paleontological Exploration (Jiang Hong)
Typography / Paleontological exploration