How Do Spiders Breathe?
A spider breathes two ways. First, it breathes through small holes in its abdomen called trachea holes. The trachea is a hollow pipe that the spider breathes through – its windpipe. The opening to the human trachea is our mouth and nose, whereas the spider’s trachea holes are on the underside of the abdomen instead. A spider does not have lungs like humans do. The trachea leads directly to the spider’s internal organs. Second, a spider absorbs oxygen through a structure called its book lungs, so named because the organ is shaped like the pages of a book. Blood flows inside the “pages” and exchanges oxygen from the air circulating between them. This is a passive process, like absorbing something through your skin. Breathing with the trachea holes is an active process, like human breathing, and is more efficient. Different spiders have trachea holes and book lungs of different sizes and in slightly different locations. More about spider parts here: