New Corpse Smell
You learn to live by smell. The intestine uses bacteria, protozoans and nematodes for digestion. Shortly after death, these microorganisms devour the intestinal wall, and leak out into the body cavity, releasing digestive enzymes enzymes into the body. Cells begin to rupture, particularly cells rich in enzymes like the liver, and those with a high water content, like the brain. Flies lay eggs at wounds and orifices, and within the first 24 hours, maggots hatch.
The transition of bite victims from life to death can be seemless, even to an observer. In the first few hours the corpse is most dangerous, because they outwardly appear to be human, and continue to exhibit normal levels of strength and dexterity, and maintain higher brain functions, including the ability to communicate; they may even continue to breath, although this is only reflexive and requires active concentration. Their responses become increasingly aggressive and feral, and their bodies will flood with epinephrine, making them very fast, strong, and violent. Freshly dead corpses can be detected through the stench of their bite wounds. Facial muscles are among the first affected by death, causing the corpses to drool. Their saliva reeks of decomposition, and bite wounds are soaked in it.
Several hours after death, rigor mortis seizes up muscles and joints. The corpses become stiff and usually lay on the ground, giving the appearance of death. During this time, livor mortis, the settling of the blood in the lower extremities, will occur, as heavier red blood cells are pulled down by gravity. The upper body becomes pale, while the lower body becomes dark and swelled with blood. As interior musculature is dissolved, the outer layer of skin separates, giving the appearance that the corpse is wearing a thin, loose-fitting plastic coating. Ammonia collects in the lungs, and usually diffuses through the mouth and nose. However, liver dysfunctions such as cirrhosis can also lead to a build up of ammonia in the body post mortem, so this should not be taken as a sign that a corpse is immobilized.
The body produces cadaverine and putrecine, amines that are heavier than air and stay low to the ground. Cadaverine is what gives semen its distinctive smell. During this time corpse hunters are the most active, using dogs to detect the higher levels of the amines in the corpse. During this phase, a knowledgeable corpse hunters can approach and incapacitate the body with impunity.
In two to three days flexibility returns to the corpse. In the absence of oxygen, intestinal microorganisms respire, releasing hydrogen sulfide and methane. These gases build up within the skin and cause bloating, and their smell attracts a second wave of insects, some of which prey upon the maggots. Blue/green discoloration and distension, as well as a purple marbling of the skin, usually beginning at the stomach, occurs. Often, these gases and fluids simply purge via the rectum, but the body cavity may rupture as well. This phase is characterized by the distinct smell of rotten eggs, and signals danger, because the strength of the smell can mask the number of corpses in the area.
At approximately three weeks the hair, nails and teeth detach, and first generation of maggots mature into adult flies. Butyric fermentation begins as bacteria metabolize glucose, creating butyric acid as a byproduct. Butyric acid accounts for 3% of butter, and can be found in parmesan cheese and vomit. This signifies the final paralysis of the corpses as the vestigial muscle tissue is broken down, and gives off a pungent, cheesy aroma. Corpses are rarely able to stand at this point, and mold develops at the places where the body touches the soil. This mold has reportedly been collected for use in “corpse liquor,” an aphrodisiac some claim to use to seduce the corpses. If the body is in danger becoming uninhabitably acidic, the microorganisms stop producing butyric acid and use an alternative process that creates butanol and acetone as byproducts. This can cover the dairy smell with a heavily alcoholic paint thinner/nail polish remover smell. As a bonus, this mix of butanol and acetone is highly flammable.