After watching Harry Potter and the Chamber of Secrets again recently, my wife and I were discussing how terrifying Acromantulas would be in real life.
“There would be no humans, we’d all be dead,” my wife proclaimed.
“Well, we don’t have to worry about that, bugs sizes are limited by the amount of oxygen in the air. You know, they all used to be bigger back in the day when oxygen levels were higher…”
She was horrified at the thought. To be fair, when I researched how large my insect nemeses could get – I had the same reaction.
300 million years ago, the atmosphere contained 35% oxygen compared to 21% now. So giant bugs were all over and zipping around. Instead of dedicated lungs, insects and arachnids rely on a less efficient system of tracheal tubes to supply oxygen.
Another issue is that exoskeletons from these invertebrates do poorly with scaling. Volume and Surface Area increase exponentially as “size” increases, and so the weight becomes too much.
Let’s all just take some time and be thankful bugs today aren’t any larger than they are… I guess Australia still has monster…