Why do octopuses and squids have blue blood

(ORDO NEWS) — Octopuses and squids are mysterious creatures of the deep. They are often portrayed as sinister hunters in movies and literature. But you must admit, their bizarre shape and behavior are really scary!

Shouldn’t blood be red in all creatures?

However, one of the strangest features of these creatures is the color of their blood. Why do octopuses and squids have blue blood? The real reason for this fact is very simple and lies in the evolution of these animals.

Let’s start by understanding why we are used to seeing red blood. One of the key components of human blood is iron. It is found in hemoglobin, a blood-borne protein that transports oxygen to organs and tissues.

Iron binds with oxygen, oxidizes, and causes the blood to turn red (in nature, we call this “rust”). Hemoglobin carries oxygen more efficiently than other substances in nature.

However, 600 million years ago things were a little different. Human beings have evolved over tens of millions of years, but long before we left the seas to become land mammals, we were simpler creatures. Probably the protein in our blood responsible for carrying oxygen was different.

More primitive species (such as the octopus, squid, and a number of other invertebrates) use a different protein called hemocyanin, which uses copper rather than iron as the binder mineral. When copper binds with oxygen, the color change occurs in a different way, resulting in the blue color of their blood.

It is important to say that hemocyanin plays a key role in the adaptation of squid and octopuses to the environment. Many of these creatures live near the seafloor, often in extreme or arctic temperatures.

In such places, oxygen adheres more densely to proteins, and if it cannot be separated in time to enter the organs, the body will suffocate. Fortunately, these deep-sea creatures can change the concentration of hemocyanin in their blood (by as much as 40% in different species) to compensate for this and ensure survival in polar waters.

There are organisms with other colors of blood! For example, there are green-blooded lizards of Papua New Guinea that break down used hemoglobin into its constituent parts (bilirubin and biliverdin). These by-products interact with the blood, giving it a green color.

There are also certain fish that live in extreme temperatures and have perfectly clear blood without any blood-borne protein oxygen carriers. Given how fish take in oxygen from their environment (in some cases gills and direct diffusion of oxygen), they can pump oxygen to the parts they need without any of those colorful carriers.


Contact us: [email protected]

Our Standards, Terms of Use: Standard Terms And Conditions.