Hair and fingernails may appear longer after death, but not because they are still growing. Instead, a persons fingernails and hair may appear longer because the skin around them has retracted, according to the Dermatology Clinic at University of Arkansas.

After death, dehydration causes the skin and other soft tissues to shrink. This occurs while the hair and nails remain the same length. This change in the body creates the optical illusion of growth people observe.

This disturbing, gruesome image is pure "moonshine" according to forensic anthropologist William Maples, who was quoted in the BMJ study. However, he explained that dehydration of the body after death can cause retraction of the skin around hair and nails, giving the illusion that they have grown. All tissues require energy to sustain their functions, and no such thing is possible once the mechanism that promotes normal growth shuts down at death.