All animals, including humans, have red blood. How about purple, green, or even colorless blood? … Here on Earth, the blood of many animals can have one of these colors. The color of an organism’s blood depends on the respiratory pigment molecule in the organism.
In another science files; the blue blood is the second most abundant. It is the color of the hemolymph of most mollusks and many groups of arthropods. It is a consequence of the pigment called hemocyanin .It is a protein that, instead of being associated with iron, is associated with copper, a metal that, when oxidized, acquires a bluish color. Thus, crabs, lobsters, spiders and scorpions, among others, could then be considered true majesties due to this bluish fluid that circulates inside their bodies.
Hemocyanin:
Hemocyanin is not found inside cells (as in the case of hemoglobin and red blood cells), but is found free in hemolymphatic fluid, one of the reasons why it is less efficient in distributing oxygen . To compensate for this problem, these organisms have evolved mechanisms such as cutaneous respiration or the extraordinary tracheal systems.
The octopus have blue blood, Blue-hued hemocyanin binds to oxygen in the blood and transports it throughout the octopus’s body to supply tissues, a critical factor in its survival. Octopuses have three hearts and need more oxygen than most other invertebrates, so the hemocyanin allows octopuses to get a steady oxygen supply, even when it isn’t readily available in their environment. The octopus is a surprisingly complex creature and, quite possibly, the world’s original “blue blood.” Its 500 million neurons are distributed throughout its head and body, compared to the 100 billion neurons in our brains.
Into the others colors that exist in another life the blue planet are:
- Red: humans
- Blue: horseshoe crab
- Green: earthworm
- Violet: lamp shells
- Clear: ice fish
Why this color:
- Red: hemoglobin
- Blue: hemocyanin
- Green: chlorocruorin
- Violet: hemerythrin
- Clear: does not contain respiratory protein.
bibliographic help:
https://es.quora.com/La-clorofila-hemoglobina-y-hemocianina
https://www.nationalgeographic.com/animals/invertebrates/facts/octopus