Hello, I'm an expert in the field of biology with a focus on marine life and their unique characteristics.

The animal whose blood is green is the hagfish. Hagfish are jawless, eel-like creatures that live in the deep sea. Their blood contains a copper-based blood pigment called hemocyanin, which is similar to the hemoglobin found in most other animals but uses copper instead of iron. This hemocyanin gives their blood a blue or greenish color. It's important to note that while the blood of hagfish may appear greenish, it's not the same as saying it is "green blood." The term "green blood" is often used metaphorically or in a fictional context, but in reality, no known animal has bright green blood.

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The blue comes from a copper-rich protein called hemocyanin, which carries oxygen from the lungs to the bloodstream and then to the cells of the octopus's body. Hemoglobin, an iron-containing protein found in the blood of other animals��including humans��serves the same oxygen-transporting function but turns blood red.read more >>