When mammals breathe, they breathe oxygen into their lungs, where it is exchanged for gas in the alveoli with the blood, and the oxygen is carried by the blood into the heart and through the arteries to the whole body for metabolic use. Mammalian blood carries oxygen by using iron in the blood as a carrier. Iron combines with oxygen to make a red color, so the blood is red.

In contrast, in the blood of lower animals, such as horseshoe crabs, oxygen is not transported by iron, but by copper. Since copper-containing proteins bind in a blue color, this gives the blood its blue color.

Expanded information:

Note:

1, horseshoe crab fish and tea can not be eaten together, if the content of vitamins is relatively high, such a food is also easily and Horseshoe crab fish mutual restraint, if eaten together, easy to produce the human body is difficult to digest the ingredients, but also inhibit the human body for the absorption of calcium.

2, in the horseshoe crab fish, because it contains a variety of bacterial viruses, plus which contains a large number of copper ions, eat horseshoe crab fish, pay attention to the right amount, or else it is easy to lead to food poisoning, affecting health.

3, horseshoe crab fish after cleaning well cut into pieces, you can use horseshoe crab fish for cooking, and it is best to eat with some ingredients, you can try to eat with the watermelon, because the watermelon refreshing flavor, you can horseshoe crab fish bitter taste removed, you can make horseshoe crab fish meat tender taste more obvious.

Baidu Encyclopedia - Horseshoe Crab Fish