The folded design creates a massive surface area in a small space, maximizing oxygen absorption. How They Work
While book lungs are common, some smaller spiders also use a (a network of tubes). book lung
Because these organs are essentially open to the air, they are prone to drying out. This is why many spiders require high humidity to breathe effectively. 💡 Key Evolution Fact The folded design creates a massive surface area
The name comes from the organ's physical structure, which resembles the stacked pages of a book: book lung
Most arachnids don't "inhale" or "exhale" like we do. Air simply flows into the spiracles and oxygen diffuses into the hemolymph naturally.