How Do Spiders Breathe?
Spiders breathe differently than humans. They don’t have a “closer” muscle that pumps air into the lungs, and instead use their tracheae to absorb oxygen.
The spider uses a small, light-colored molecule called hemocyanin to transport oxygen and carbon dioxide. It works like the red blood cells in human blood.
The trachea is a network of narrow tubes lined with a hard substance called chitin. These tubes open to the surface through tiny holes and spiracles.
There are several types of spiders with different respiratory systems. Some of these have only one trachea, while others have two or more. Most have both.
To breathe underwater, some spiders form an air bubble around themselves. In some species, this air bubble can sustain a spider’s body for over 24 hours. As the spider resurfaces, it deposits a bubble of air from the surface into its silk air tank.
Another type of air-breathing spider is the tarantula. Its lungs are much different from those of mammals. Instead of being able to pump oxygen into its blood, a tarantula’s lungs carry the waste product of its metabolism.
One interesting feature of spiders is their ability to survive for months without food. In fact, some species can survive for as long as ten months in a plastic box without feeding. This is due to their use of a complex filtering system.
Arachnologists believe that the new trachea was a later development in the evolutionary history of spiders.