I accidentally crushed another ickle spider in the barn (it’s that frenzied time of year) and it got me thinking, do people realise spider blood is bluish?
In humans a protein inside red blood cells called haemoglobin carries oxygen molecules. Human blood is red because haemoglobin contains oxygenated air.
In spiders the protein haemocyanin contains oxygenated copper. It is not stored in blood cells and circulates unabated in the hemocoel. Crustaceans, octopus, and squid also have blue blood.
This has been your trivial information post of the day.