The yellow substance on the head of crayfish is shrimp yellow. When the mother shrimp is mature, the head and neck will contain shrimp yellow, so the shrimp with shrimp yellow must be the mother shrimp, but not the male shrimp. The mother shrimp is immature and can't see the shrimp yellow. Most people are familiar with crab roe, but they know little about shrimp. Before pregnant with eggs, the mother shrimp contains shrimp in her head and neck, commonly known as "red-headed baby". Eating lobster, in addition to shrimp meat, tempting shrimp yellow is also a favorite of many people.
Extended data:
Although the shrimp yellow of lobster can be eaten, it is still not recommended, because there are not only shrimp yellow on the head, but also shrimp internal organs, which are not easy to remove.
Lobster shrimp has almost no other organs except one intestine, and all organs are concentrated in the head. It includes stomach, liver, heart, a pair of testes/ovaries, antenna glands of excretory organs, bladder and excretory orifice. In other words, eating shrimp head means eating dirty things such as shrimp excrement, semi-digested shrimp food and shrimp urine together.