Human decomposition is a natural and complex biological process that begins shortly after death. This process involves a series of physical and chemical changes as the body breaks down.
Visible Changes at One Week
After approximately one week, a human body typically exhibits significant visible changes, largely due to the accumulation of gases and the activity of microorganisms. The most noticeable change is often bloating, where internal gases cause distension, particularly in the abdomen, face, and limbs. This swelling can make the body appear significantly larger.
Alongside bloating, distinct discolorations appear on the skin. The skin may take on a greenish hue, especially in the abdominal area, and a web-like pattern of greenish-black or reddish-brown veins, known as marbling, can become visible. This marbling occurs as blood breaks down and discolors the vessels. The face and eyes may also become swollen and discolored.
Skin slippage and blistering are also common during this period. The outer layers of the skin may loosen and separate from the underlying tissues, forming fluid-filled blisters. Once these blisters rupture, the skin can peel away, sometimes resembling a severe sunburn. A strong, distinctive odor, often described as foul or putrid, becomes very apparent, resulting from the gases and compounds released during tissue breakdown.
Insect activity, particularly that of flies and their larvae (maggots), is typically well underway by one week. Flies are often attracted to a body within hours of death and lay eggs, which hatch into maggots that consume decaying tissue. The presence of these insects can greatly accelerate the decomposition process, especially in warmer conditions.
Underlying Biological Processes
The visible changes observed in a decomposing body are driven by fundamental biological processes occurring at a cellular and microbial level. One of the initial processes is autolysis, or self-digestion, which begins within minutes of death. When circulation and oxygen supply cease, cells become deprived of oxygen, leading to an increase in acidity within them.
This acidic environment causes cellular membranes to rupture, releasing enzymes that then begin to break down the cell itself and its connections to other cells. This process contributes to the softening of tissues and the formation of blisters.
Following autolysis, putrefaction becomes the predominant process. Putrefaction involves the breakdown of tissues by bacteria, primarily anaerobic bacteria that were already present in the gut before death. These bacteria proliferate and spread throughout the body, feeding on proteins and carbohydrates. As they consume tissues, they produce various gases, including hydrogen sulfide and methane, which cause the body to bloat and release strong odors.
Factors Affecting Decomposition Rate
The exact appearance of a body after one week can vary significantly due to several influencing factors that either accelerate or slow the decomposition rate. Temperature is a primary factor; warmer temperatures generally accelerate decomposition because heat promotes the activity of bacteria and enzymes. Conversely, colder temperatures slow down these biological processes, preserving the body for longer periods.
Humidity and moisture also play a substantial role. High humidity creates a moist environment that encourages bacterial growth and insect activity, speeding up decomposition. In contrast, very dry conditions can lead to mummification, where tissues dry out and harden, significantly slowing the process. The environment where the body is located also influences the rate; bodies exposed to air generally decompose faster than those submerged in water or buried in soil, as air provides more oxygen for aerobic bacteria and easier access for insects.
Clothing or other coverings can impact decomposition. Clothing may trap heat and moisture, potentially accelerating bacterial activity, or it can slow decomposition by acting as a barrier to insects or by insulating the body. Body characteristics, such as body size and fat content, can also influence the rate. Larger bodies with more fat may initially decompose faster due to more tissue for consumption, but excess fat can also act as an insulator, slowing initial stages. Additionally, the cause of death can influence the rate, with traumatic injuries potentially accelerating decomposition by providing entry points for bacteria.