Why were animals so much bigger in prehistoric times?

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Dinosaurs seemed to have generally been so much larger than animals today. Huge dragonflies that dwarf their modern counterparts, turtles 10ft long. What is the mechanism that allowed them to be so large, or conversely makes modern ones smaller? Is it about Oxygen levels, or efficiency, or something else?

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Anonymous 0 Comments

For vertebrates, I think the limiting factor is usually availability of food. Being big requires a large energy intake. Life is not as abundant today as it was back then (remember we are still technically in an ice age). It’s not so evolutionarily advantageous to be huge.

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