Though not all dinosaurs were behemoths, some grew to be more than 100 feet (30 meters) tall. Experts have always wondered what made the creatures grow so tall, and now they are starting to form a picture of the factors that interacted to make this a reality
Some of the contributing factors may sound weird at first, such as for example that fact that they lay eggs, or that they had extremely efficient lungs and respiratory system. At the same time, the theory stating that animals tend to increase their sizes as they evolve was proven not to be true, LiveScience
Researchers say that they analyzed about 400 species of dinosaurs that lived between the late Permian and the middle Jurassic periods. Overall, it was found that various species went their own evolutionary ways, some growing to extreme heights, while other diminishing their average size over 100 million years.