Spiders do not “hold their breath” like humans or other mammals. Unlike vertebrates with active respiratory muscles, spiders possess a unique respiratory system. This means they cannot consciously stop breathing or hold air in their bodies. Instead, their survival relies on the efficient design of specialized gas exchange organs.
How Spiders Breathe
Spiders utilize two primary respiratory organs: book lungs and tracheal systems. Book lungs, found in many spiders, are hardened pockets on the underside of the abdomen. Within these, thin, leaflike lamellae are stacked like pages, providing a large surface area for efficient gas exchange. Oxygen and carbon dioxide diffuse between air in these spaces and the hemolymph, the spider’s circulatory fluid, flowing within the lamellae.
Many spiders also possess a tracheal system, a network of tubes extending throughout their body to deliver oxygen directly to tissues. These tubes open externally through small pores called spiracles, usually on the abdomen. While book lungs are the main respiratory organs for many species, tracheal systems play a significant role, especially in smaller, more active spiders or in conjunction with book lungs. For example, tarantulas primarily use two pairs of book lungs, while wolf spiders have both.
Gas exchange in both systems occurs through passive diffusion, meaning there is no active pumping of air. Hemolymph, containing a copper-based respiratory pigment called hemocyanin, transports oxygen throughout the spider’s body, similar to human hemoglobin. While book lung openings can expand or contract, they never fully close, allowing for continuous, passive gas exchange. This passive process is a key distinction from active breathing mechanisms in mammals.
Spider Survival in Low Oxygen Environments
Spiders’ ability to endure low-oxygen conditions or submersion depends on their unique physiology. They generally exhibit a low metabolic rate compared to many other arthropods, which reduces their oxygen demand. This low metabolic activity allows them to survive for extended periods with limited oxygen, as their bodies consume less energy. Some species can even reduce their metabolism further when faced with oxygen scarcity or lack of food.
When submerged in water, some spiders can survive for minutes to hours, or even longer. This often involves trapping a thin film of air around their bodies using water-repellent hairs. This trapped air bubble acts as a physical gill, allowing limited gas exchange with the surrounding water. For example, a tropical spider has been observed hiding underwater for up to 30 minutes by maintaining such an air film.
Factors such as species, body size, and temperature influence how long a spider can survive in low-oxygen conditions. Smaller spiders with lower oxygen requirements may endure longer than larger ones. Cooler temperatures can also slow down a spider’s metabolism, extending their survival time. While some aquatic spiders, like the diving bell spider, have specialized adaptations to live underwater for days by building air-filled silk structures, most terrestrial spiders cannot survive indefinitely when submerged.