The blood of an insect functions differently than the blood of a human. In humans, blood gets its red color from hemoglobin, which travels through blood vessels carrying oxygen from the lungs to the rest of the body. Insect blood, however, does not carry gasses and has no hemoglobin.
Kimberly Sessions, of Atlanta, Georgia wrote to A Moment of Science with the following question: “I know why the ocean is still salty: evaporated water leaves the salt behind. But how did it get salty in the first place?”
The chemicals that cause this reaction are stored in our nerve endings, and when we die, they’re gradually released.