How long does it takes for a human corpse decompose?

Question

If possible explain it by stages eg. when it start to turn pale and smell.

Answer 1

Depends on a lot of things like temperature, humidity, if bacteria/fungus capable of decomposing are present, how large the person is, when the last time they ate was, fat decomposes at different speeds then flesh and muscle and cause of death. Usually, for an unburied body 8-12 days.

Also you can have other animals (and plants) that will speed up the process.

Lots of insects can devourer a corpse in under a week but this may not fall under your definition of decomp.

Some chemicals like strong highly concentrated acids and bases can liquefy a body in a couple of hours.

For micro organism decomposition (bacteria, fungi, excreta.) keeping the corpse warm and moist a corpse can be gone in 5-12 days above ground.

If the body is buried it takes longer to decompose, if it is contained (like in a coffin) it takes even longer. "Although an exposed human body in optimum conditions can be reduced to bone in 10 days, a body that is buried 1.2 m under the ground retains most of its tissue for a year" (quote from the web page I list as a source)

If the body is embalmed it may take a several months before it is mostly decomposed.

Really this all comes down to when and how you consider a corpse decomposed.

There are many different stages of decomp. These not all stages are present in all cases, for instance you can have external decomp and internal together or just one at a time.

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Warning- this part in may be gruesome:
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Assuming a body left untouched, died of natural causes:

Pale skin will show up with in minutes of death because blood has stopped circulating.

Typically the internal flesh of the large intestine will start first. Our intestine is littered with rotting/decaying organic matter all the time (poop) and our body is only able to stop the bacteria from rotting us when we are alive.

When our digestive tract bursts it will release digestive enzymes that will digest our internal body most efficiently if our body is kept at living body temperature. This is where temperature can mean the difference in days and months of decomp. The body will release bile, which has a particularly awful smell.

Gas from bacteria make the corpse bloat up with hydrogen sulphide, methane, cadaverine and putrescine. Fat cells will liquefy and bacteria will thrive on them, the bacteria in our colon (large intestine) will have a field day. This is where the body will really start to stink.

The external flesh starts to decompose shortly after death this is because we have millions of bacteria on us all the time. Colonies of bacteria will form first in small circles in places that are the most moist and warm (mouth, arm pits, lungs).

The smell of the rotting corpse will attract Demetrius organisms like flies who will use their own vomit (actually regurgitate digestive enzymes) to assist in decomp with the purpose of making it easier for the fly to digest, and then they will lay eggs. When the larvae hatch it may be only a few days more until the corpse is simply bones, teeth, hair and finger/toe nails.

Over time (many years) the bones will dry out, crack and crumble to become dust, and the corpse is no more.

www.deathonline.net lists the following stages of decomp.
Stages of Decompostion
Living
Initial decay
Putrefaction
Black putrefaction
Butyric fermentation
Dry decay

www.bbc.co.uk/health/ask_the_doctor/decompostionafterdeath.shtml states that "Decomposition in the air is twice as fast as when the body is under water and four times as fast as underground."

Answer 2

This is a really hard question to answer. Rather morbid really.
Decomposition depends on the bacteria present, weather conditions, containment of the body and many other factors.
For instance, an acid or alkali added to a body in a 44 gallon drum can dramatically increase the rate of decomposition. A body in a nice warm environment, a healthy supply of bacteria and a few maggots from flies would be very quick. Add a slime mould and some fungi and it would be even faster.
Now, take a corpse to the the bottom of deep freshwater lake where the water is very cold, it could take years. Dump the corpse in a a freshwater river and it, if it is not wearing cement boots, could float within 24 hours due to gas build up in the stomach.
I think you need to refine your question.

Answer 3

An unburied human body will be reduced to bones and hair in about 10 days under optimal (ideal) conditions. The duration beyond that depends on the conditions of the burial. Humans have been ritually burying their dead for long time. When archaeologists first began finding accumulations of human and neanderthal bones in caves they concluded that this was where we used to live. Since then we now understand that caves were the burial ground of choice and that the notion of the "cave man" is actually mostly misunderstood - it's not where we lived, it's where we were put after we died.

Answer 4

50 years

Answer 5

Depends on the temperature of the environment.