From what I read recently (and I don't remember where it was), the current thinking is that it wasn't oxygen levels or temperatures, but the lack of predators that let dragonflies grow that big. A big dragonfly is much slower and an easier target. So unless you get rid of birds, you won't have giant dragonflies.
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From what I read recently (and I don't remember where it was), the current thinking is that it wasn't oxygen levels or temperatures, but the lack of predators that let dragonflies grow that big. A big dragonfly is much slower and an easier target. So unless you get rid of birds, you won't have giant dragonflies.