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squid,octopus,horseshoe crab and certain insects and their larval stages have blue coloured blood.
The Antarctic octopus (Cirro Octopus antarctica) is known to have blueblood. This is because its blood has a copper rich protein.
Sometimes blood can look blue through our skin. But blue blood does exist elsewhere in the animal world. It's common in animals such as squid and horseshoe crabs, whose blood relies on a chemical called hemocyanin, which contains a copper atom, to carry oxygen.