| || ||Copper has another biological function in animals such as snails, lobsters and spiders. It is part of their blue blood! |
Vertebrates (including humans) have red blood. The colour comes from a special molecule called haemoglobin, which is found in red blood cells. Haemoglobin carries oxygen around the body and its key element is iron.
On the other hand, some invertebrates rely on a molecule called haemocyanin to carry oxygen around their bodies. Snails, lobsters and spiders actually have blue blood (properly called haemolymph). The colour comes from the haemocyanin molecule, which is blue. It is dissolved directly into their 'blood' instead of being enclosed in blood cells.