Book Lung Apr 2026

While book lungs are common, some smaller spiders also use a (a network of tubes).

A "book lung" is a specialized respiratory organ used for atmospheric gas exchange by many arachnids, such as spiders and scorpions. Unlike human lungs, these organs are not connected to a complex throat or nose system; instead, they open directly to the outside air through small slits on the abdomen called spiracles. Anatomy of a "Book" book lung

Book lungs are believed to have evolved from , which are found in aquatic ancestors like horseshoe crabs. When these creatures moved from water to land, the gills were internalized to prevent them from drying out, becoming the book lungs we see today. Comparison: Book Lungs vs. Tracheae While book lungs are common, some smaller spiders