Why Do Dead Bodies Sometimes Make Noise?

Let's be honest: If you were making your way past or through a cemetery and you started hearing all this clatter and commotion from under the ground, you'd definitely freak out. Like, really, really freak out and imagine a "Night of the Living Dead" situation where the shambling, decaying corpses of the damned and hangry moan across the earth in search of succulent humanoid flesh. So good news: If we talk about dead bodies "making noise," we're not talking about the gnashing of undead teeth or noisy corpses banging out a ripping drum solo or something. Yes, corpses can produce sounds, but only because of the same thing that produces sound anywhere else: shifting air and gas. 

Folks might be familiar with some typical things that happen after death, like the body evacuating itself of solids and liquids. This very undignified happening occurs because muscles across the body lose tension after death, and if you've got a full bladder or ready bowels, you're going to go. Then there's the postmortem fingernail growth myth, which is actually the skin around the nails receding and making them look longer as a result. And noisy corpses? Corpses can produce sound if there's any gas left in the body after death. Speaking to The Healthy, Dr. Mary Lachman said air might pass through the vocal chords and sound like groaning or moaning, while gases throughout the body might squeak, peep, squeal, or anything else.

Failed resuscitation and bacteria

It can be disturbing to talk about what happens to a body after death because until the moment of death, that body was a person. It can be especially difficult if someone has ever experienced the sudden death of a loved one — perhaps even a loved one who made it all the way to an emergency room before receiving medical care and dying there, anyway. In fact, this ER scenario is likely to cause a greater buildup of air in the body. 

Health and wellness expert Caleb Backe discussed this scenario with Bustle, noting that emergency care workers often pump air into the lungs and stomach when attempting to revive somebody. Digging down into details, the reader can imagine an emergency care worker performing CPR on a patient, that patient passing away during CPR, and then the weight of chest compressions pushing air out of the lungs and possibly even the stomach. But even if this precise chain of events doesn't happen, a body will exude air if it's moved, which it will have to be at some point after death. Backe says that this scenario is "extremely common."

Even if resuscitation attempts don't produce extra gas inside a person's body, bodily bacteria do. Mayo Clinic gastroenterologist Purna Kashyap told NPR that bodily bacteria — particularly gut bacteria — produce sulfide gas. McGill University further explains that bacteria are "free to roam around and digest our tissues" after death, which would produce more gas.

The death rattle

If anything, talk of dead bodies producing sound might call to mind a term that's passed through popular media here and there: the "death rattle." MedicalNewsToday describes a death rattle as a "crackling, wet noise" in the back of the throat as someone approaches death because of an accumulation of fluid. Death typically occurs within 25 hours of the onset of death rattles, which may be interspersed with sharp, irregular breathing and other symptoms. 

HPC Consultation Services says that the term "death rattle" is misleading, however. As a person approaches death breathing becomes a "solely involuntary act," meaning that a person approaching the end of life loses conscious control over breathing. Management of breathing passes to one of the most fundamental parts of the brain, the brain stem, which regulates breathing as a kind of "reflexive" act. Such breathing can roll over to what's called agonal breathing. Avive explains agonal breathing as sounding and looking like harsh, sudden gasps for air with jerky muscle movement as well as grunting, snoring, snorting, and more.  

If the slide to death is slow, HPC Consultation Services also says that someone may experience apneic breathing, or a diminished frequency of breaths. The space between breaths may grow longer and longer until finally, the person takes their last one. Eventually, this final exhalation will span from life to death and be the very first noise a person makes when dead, before any other.