Estimating the Time of Death: Algor Mortis

Algor Mortis is the last of the three Cardinal changes occurring to a body following death. The other two, Rigor Mortis and Livor Mortis have been covered before on this blog. Algor Mortis is the postmortem cooling of the body. Technically, it’s the acclimation of body temperature to the environmental temperatures. The healthy human body in life maintains a temperature of about 98 degrees Fahrenheit (37 degrees Celsius). If the air temperature is lower the body will cool and if the temperatures are higher then the body will warm. Typically these measurements are taken by inserting a probe into the liver (at least twice with an hour between).  Oral temperatures are not reliable examples of core body temperatures and are not used.

There are a number of things that can affect how quickly the core body temperature acclimates.  Some of those conditions include the type and amount of clothing the victim is wearing, or if the victim is wrapped (like in plastic sheeting). Bodies with a lot of clothing will be more insulated from the environment and thus cool more slowly. Body mass also influences temperature change. Environmental temperatures obviously influence this process and some areas see dramatic swings in temperatures in short periods of time. My readers in Colorado are very familiar with this. We can have a white-out blizzard in the morning and have clear skies and 50 degrees F by lunch. If the clothing or wrappings are wet then that will have an influence as well, especially when temperatures swing between freeze and thaw.

Adding to all of these considerations is the realization that decomposition is not a static process. Scavengers (vertebrate and arthropod) can significantly alter coverings and body mass at unpredictable rates. Over the years, scientists have attempted to develop various formulas to estimate the time since death using changes in core body temperature. However, due to the variations experienced during decomposition these formulas are not considered reliable.

As an author, you should probably avoid having characters put too much emphasis on Algor Mortis estimations or readings unless you want to set your characters up to be in error. This can be a useful tool, especially if the character you want to “set-up” is not directly involved in the forensic sciences (like a hospital pathologist or family doctor). You could create some tension between the police, victim’s family, and a hospital pathologist using an over-reliance on postmortem body temperature levels. Your Coroner/Medical Examiner or entomologist character will most likely be able to settle the issue with finality and use other postmortem changes to estimate the time since death.