Imagine that during a walk you find a cat that has just died in a corner. Although the body apparently appears to be in good condition , the reality is that its disintegration has already begun within it : the millions of bacteria that before death fed on what passed through the intestine do not die with their host and start to devour it, making good the well-known saying of “raise crows…”.
Not content with this, as they digest it they make their way to other organs; the feast is served. The body’s own digestive enzymes collaborate in the process, which, when released from their natural place, spread throughout the body.
But still many cells are still alive. For example , in humans, brain cells take between 3 and 7 minutes to die, while skin cells can be extracted from a dead body 24 hours later and grown as if nothing had happened in a laboratory culture . This does not mean that the popular idea that nails and hair continue to grow after death is true : it is an optical effect because the dehydration that occurs after death causes the skin to retract and part of the hair appears and nails that were previously hidden. Sometimes a stiffening of the muscles can occur and postmortem spasms can occur, which are so scary if they happen in humans.
At the same time that the bacteria gnaw at the poor kitty, a massive autolysis occurs, the cells self-destruct. This happens because the lysosome , an organelle that contains digestive enzymes that are used to eliminate dead cells or in cleaning tasks inside the cell itself, releases its enzymes, which begin to digest it: the cat is -literally- eating from the inside .
While outside the flies and blowflies have realized that the poor devil is dead and begin to lay their eggs both around possible wounds and in the natural orifices of the body: mouth, nose, eyes, anus and genital organs.
After three days , the bacteria have been doing their job and releasing different fluids – let’s remember that dirty and smelly water that sometimes comes out of a garbage bag that we have forgotten to take down when returning from a trip – and stinking the surrounding environment with molecules such as methane, hydrogen sulfide (with its characteristic smell of rotten eggs) and others with names as striking and insinuating as putrescine and cadaverine . It is obvious that humans would never use them in their perfumes, but their aroma is irresistible to a wide variety of insects. The gas released by internal decomposition has a curious effect: it inflates the body and forces cells and blood vessels to lose their fluids and scatter.
Newly hatched fly larvae move about the body, feasting on the company of their bacterial cohort, for whom decomposing matter is heaven. The process is accelerated, the rotten smell is accentuated , and this attracts more insects, such as mites and beetles . Among the new arrivals is the flesh fly , which like beetles are predators that feed on both rotting meat and larvae. Of course, take advantage of the situation to also leave their own eggs. Parasitoid wasps also appear, which insert their eggs into larvae of other species or paralyze the adult insect and inject them inside or, being more restrained, deposit them on it.
After two weeks the body deflates and the meat acquires a creamy consistency . The color black is dominant, the smell becomes unbearable for the human sense of smell, puddles form around the corpse and the number of insects present in different stages of development suggests that a mega-party is being celebrated. Its activity increases the temperature of what remains of the deceased, which accelerates its decomposition by bacterial action. Those larvae that are already satiated, plow the ground and become pupae. This situation attracts stone beetles and wasps even more, which see in these mature larvae a phenomenal host for their future offspring.
A month later, what is called butyric fermentation begins, named for the smell of cheese that emanates from the carcass and that attracts other types of insects, such as the cheese fly , which begins to account for how little they have left. who came first. Interestingly, it is the larvae of this insect that are introduced into pecorino cheese to obtain casu marzu in Sardinia. It is also the insect that is most frequently found in the human intestines, since stomach acids do not destroy it, and it produces an enteric myiasis : vomiting, abdominal pain and bloody diarrhea are its symptoms.
The few larvae that remain, and that until then have feasted on the meat, begin to abandon the party as only the ligaments and skin remain. However, for the beetle these parts are the most succulent, and they are the ones that are at this stage of decomposition. For its part, the mold continues to grow on the part of the carcass in contact with the ground. The party comes to an end.
The corpse, completely dehydrated, slowly decomposes and only the bones remain. If the poor thing had hair, the moths will be taking notice of it and the mites will continue to eat the microorganisms that still swarm around the place.
