Blood based on hemocyanin rather than hemoglobin. Hemocyanin is based on copper rather than iron, and as a result the blood is blue rather than red. Hemocyanin works more efficiently at cold temperatures than warm temperatures, unlike hemoglobin.
The octopus is a cool blooded creature, unlike lizards which are generally cold blooded, with exceptions such as the tegu, which is warm blooded during mating season.
by Ravenious December 13, 2020