The established explanation for the demise of giant insects has collapsed, suggesting their respiratory systems were more robust than assumed. This severs the simple link between atmospheric oxygen and body size, forcing a search for a new culprit. The key question now is what other pressure—such as the rise of agile avian predators—truly ended the age of giants.
The established explanation for the demise of giant insects has collapsed. For decades, the decline in atmospheric oxygen was cited as the primary reason creatures like two-foot-long dragonflies disappeared. New analysis, however, indicates their respiratory systems were more robust than assumed and could have compensated for lower oxygen levels. This finding severs the simple, accepted link between atmospheric oxygen and insect body size, forcing a fundamental reevaluation of prehistoric extinction drivers.
With the oxygen theory now in doubt, the search is on for a new culprit. The collapse of one dominant explanation creates a vacuum, suggesting our understanding of the constraints on evolution is incomplete. The key question now is what other pressure truly ended the age of the giant insects. Attention is turning toward new ecological pressures, with the rise of agile avian predators emerging as a leading alternative hypothesis to investigate.
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