Do spiders have hearts and blood?
Spiders, like most arthropods , have an open circulatory system, i.e., they do not have true blood, or veins which transport it. Rather, their bodies are filled with haemolymph, which is pumped through arteries by a heart into spaces called sinuses surrounding their internal organs.
In spiders, and in many other arthropods (as crustaceans) and also in most mollusks the oxigen is bound to a different molecule called hemocyanin that contains copper instead of iron. The hemocyanins are proteins colourless in the reduced or deoxygenated state but the oxydized copper beeing blue/green, gives that colour to the oxygenated blood.
Spiders (as well as horseshoe crabs and certain other arthropods) have blue blood due to the presence of copper-based hemocyanin in their blood. Some animals, such as the sea cucumbers, even have yellow blood. What could make blood yellow? The yellow coloration is due to a high concentration of the yellow vanadium -based pigment, vanabin.
Spiders have transparent blood. False – Spiders have blue blood. In human blood oxygen is bound to hemoglobin which contains iron, giving it the blood a red color. In spiders, as well as other Arthropods and Molluscs, oxygen is bound to hemocyanin which contains copper, giving its blood a blue color. The same interaction that causes oxygenated blood to color, also causes iron rust to appear reddish and the oxidized copper to appear green.
A spider going for a walk is deeply impressive. All eight legs are attached to the front part of the spider, the prosoma or cephalothorax, which also carries the eyes and mouthparts. Inside the prosoma there’s a fluid called hemolymph that takes the place of blood.
Spider Blood Unlike humans, spiders have an open circulatory system. The spider’s simple heart — a tube surrounded by a muscle, with a one-way valve on each end — pumps blood into the body cavity, all around the spider’s organs. Organs get oxygen because they’re soaking in blood.