Lobster blood is typically a clear or pale blue color due to the presence of hemocyanin, a copper-based molecule that functions similarly to hemoglobin in red blood cells. Instead of iron, which gives human blood its red color, hemocyanin contains copper. This adaptation is particularly suited to the marine environment, where lobsters thrive. When lobsters are exposed to oxygen, their blood takes on a blue hue, while in its deoxygenated state, it is more of a clear or light yellowish color. This unique feature exemplifies the diverse ways in which different organisms have evolved to transport oxygen.