Here's a creepy question to ponder: Do hair and fingernails continue to grow after a person dies?
The short answer is no, though it may not seem that way to the casual observer. That's because after death, the human body dehydrates, causing the skin to shrink. This shrinking exposes the parts of the nails and hair that were once under the skin, causing them to appear longer than before, said Dr. Doris Day, a dermatologist in New York City and an attending physician at Lenox Hill Hospital, also in New York.
Typically, fingernails grow about 0.1 millimeters (0.004 inches) a day. But in order to grow, they need glucose — a simple sugar that helps to power the body.
Related: Is faking your own death a crime?
"Once your body dies, there's no more glucose," Day told Live Science. "So skin cells, hair cells and nail cells no longer turn over and produce new cells."
Moreover, a complex hormonal regulation directs the growth of hair and nails, none of which is possible once a person perishes, according to a 2007 study in the journal The BMJ.
Regardless, popular culture often gets this fact wrong. In the book "All Quiet on the Western Front," the protagonist imagines his dead friend's nails growing in corkscrews after death, the researchers of the study said. They also noted that even Johnny Carson got his facts wrong when he joked about it, saying, "For three days after death, hair and fingernails continue to grow, but phone calls taper off."
Original article on Live Science.
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Laura is the archaeology and Life's Little Mysteries editor at Live Science. She also reports on general science, including paleontology. Her work has appeared in The New York Times, Scholastic, Popular Science and Spectrum, a site on autism research. She has won multiple awards from the Society of Professional Journalists and the Washington Newspaper Publishers Association for her reporting at a weekly newspaper near Seattle. Laura holds a bachelor's degree in English literature and psychology from Washington University in St. Louis and a master's degree in science writing from NYU.