Besides their terrifying appearance and immense power of dinosaurs, another thing has bewildered experts, and the general public upon their discovery is their gigantic size. With all the fossil evidence, there is no doubt that these creatures were more massive than the extant species we know and are living today. But, of course, every fascination requires an explanation. Why were prehistoric dinosaurs so big? What was the benefit of their large size? Those are questions that have wracked the nerves of biologists and paleontologists for the longest time, resulting in various theories about the dinosaurs’ massive size.
The first theory suggests that the gigantic size of dinosaurs was brought by vegetation. The creatures thrived during the Mesozoic period when the carbon dioxide levels were much higher than what is present now in the atmosphere. The abundance of carbon dioxide means an increase in temperature, implying that the climate during the era of the dinosaurs was so much warmer than today.
Plants convert carbon dioxide and water into food through the process of photosynthesis. Adding high levels of CO2 to the increased temperatures means that the period when the dinosaurs lived was blessed with different kinds of vegetation, from plants to mosses, trees, etc. With that, it is believed that sauropods, the enormous plant-eating dinosaurs, evolved to be gigantic since there was an oversupply of food. The carnivorous species of dinosaurs followed suit and grew more substantial so they can match the herbivore’s immense size.
The second theory revolves around the benefit dinosaurs’ can get from their large size – self-defense. Experts believe that these prehistoric creatures would not have grown that much if they are not getting any advantage of it. For instance, a full-grown large, bulky plant-eating Apatosaurus may be harder to take down, even if its predator hunts it down in packs. That scenario supports the basic concept of evolution that a creature changes since it advantageous because otherwise, it would not have evolved in the first place.
The third theory focuses on the idea that dinosaurs are cold-blooded animals. Cold-blooded animals, such as fish and reptiles, grow throughout their lives, which might be the case why these giants grew up their size. Experts cite two reasons why dinosaurs were deemed cold-blooded. First, a warm-blooded dinosaur will quickly heat up from the inside out, resulting in its death. Second, there are no terrestrial warm-blooded mammal extant today that can match up the size of the enormous dinosaurs.
Here’s another advantage being gigantic gives. If cold-blooded dinosaurs evolved to sufficient sizes, they could reach a state of homeothermy. It is the capability to maintain stable interior temperature, regardless of the exterior influences from the environment. That way, a homeothermic dinosaur won’t warm up rapidly amid a hot day, the same thing with cooling down at night, continually providing it with pretty average body temperature.
Now, the last theory tends to be a little different as it focuses on the bony structure of these behemoths. Experts found out that nearly 91% of all the predatory dinosaurs possessed body ornaments in the head, such as horns, bumps, and crests. The creatures sporting ornamentations grew quickly through evolution, as greater size aided in both hunting and self-defense. With that, the advantageous traits of having such size and features have been passed down and inherited rapidly, allowing dinosaurs to grow in large sizes.
As millions of years have passed, it is quite challenging to determine which of these theories accurately explains best why dinosaurs grew up so big. One thing is for sure, though – evolution is a humongous part of it.
You Might Also Like:
- Which is the largest bird in the world?
- If human civilization ended tomorrow, how long would it take for all evidence of our existence to disappear?
- How do scientists find out the temperature of the earth thousands of years ago?
- How big is the largest dinosaur egg found so far?
- What is responsible for the extinction of dinosaurs, asteroid impact or volcanic eruptions?