Why are prehistoric animals so much bigger than animals today?

When talking about ancient dinosaurs and other prehistoric animals, one of the first things that came to mind was that they were incredibly large, many times larger than animals today.

Based on the remaining fossils, scientists have discovered the existence of some dinosaurs with the height of a 6-storey building, or some dinosaurs weighing up to 45 tons.

Compared with the world's largest terrestrial mammals such as the African jungle elephant, which can weigh up to 6 tons, up to 7.5 m long and up to 3.3 m high, it is clear that the animals prehistoric objects are much larger in size.

So what is the cause of that difference?

Living environment

Habitat with abundant oxygen contributes to encouraging the growth of the size of animals.

Prehistoric Earth is a homogeneous array of continents with huge area and thriving flora. The extensive living environment and the abundant oxygen content in the air are thought to contribute to the growth of animals.

Besides, the oxygen concentration in the air is lower than current. So prehistoric animals have developed special systems that can use oxygen in the air more efficiently.

According to the study, animals with strong lung structures are often able to grow in size . The greater the amount of oxygen absorbed, combined with the fresh air, will help the animals become healthier and bigger over generations.

Evolutionary properties

In fact, not every animal that lived in prehistoric times has a huge size. For a variety of reasons, there are species that follow the evolutionary path with smaller size over time, while others have evolved in a larger and larger way in size.

During the reign of dinosaurs, the concentration of CO2 in the atmosphere was higher than we see today. This also means plants grow taller. Therefore, to eat plants in the forest, animals have to grow higher.

Through an evolution that lasted for millions of years, large animals gradually became complete.

Gradually over time, large species became the rulers of Earth in ancient times. The smaller creatures, meanwhile, must either accept their fate or live in ruin or be exterminated.

As the ground was filled with giant creatures, they continued to hybridize and create new generations of descendants that possessed the same size. Through evolution that lasted for millions of years, the large animals gradually became complete and achieved huge sizes and ideal muscles.

The constant change of the Earth

Try to put the problem back to the question " why are animals today not as big as prehistoric animals?"

The answer comes from the changing climate of the Earth, the separation of continents, and most importantly the rise of better adaptive animals.

An oversized body always comes with a big demand for oxygen and food.

In fact, giant creatures are always the ones who are most affected and are difficult to adapt to climate change disasters. The sharp decline in oxygen and the sudden decrease in food are the two main causes leading to the destruction of giant species, such as the extinction of dinosaurs.

Obviously, an oversized body always comes with a big demand for oxygen and food. Meanwhile, small animals with less need for food proved more in line with the change of the Earth millions of years later. This has led to the fact that most animals have evolved in a moderate size, instead of increasing in size.

Among the animals that appeared several million years ago, humans became one of the species with many evolutionary characteristics suited to the times. The ability to think and especially the ability to combine superior groups helped people overcome other species to become global hegemony.

Up to this point, even the appearance of giant creatures could not exist because the habitat was gradually isolated by humans. They surrender to the collective power of man, are destroyed to extinction or human race over time.