BrainStuff Classics: Why Are Peat Bogs So Good at Preserving Human Remains?

Human bodies buried in bogs can retain some features -- like perfectly preserved skin, right down to forehead wrinkles -- for thousands of years. Learn how this natural mummification process works in today's classic episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeartRadio. Hey brain Stuff,
Lauren Vogel bomb here with a classic episode from our archives.
In this one, we go deep into one of my
favorite subjects, bogs, to dig into the question of why
they're so specifically good at preserving human remains. Hey brain Stuff,

(00:24):
lurinvogl bomb here. Bogs are pretty awesome as far as
sweeping mudfields of dead buried plants go. They store the
energy of generations of plants in their mass, which can
be harvested as peat. They're also havens for mummies. Artifacts
buried beneath bogs, including human bodies, may be kept in
astonishingly good condition for thousands and thousands of years. They've

(00:45):
all got stories to tell, and today we'll look at
the weird science that makes their preservation possible. Common in cool,
wet parts of the world, bogs are water logged grounds
that form one decaying plant matter known as pete, accumulates
in low lying areas. Bogs are usually found in cool
climates and often in lake basins created by ice age

(01:06):
glaciers that no longer get a steady flow of river
or stream water. Over time, mosses cover the heap like
a blanket, and in most cases, this mossy layer is
primarily made of a mosque called sphagnum. Sphagnum moss has
the power to transform an entire landscape. Water or dirt
trapped beneath sheets of it will be cut off from
the normal supply of oxygen from the atmosphere. Also, sphagnum

(01:28):
soaks up calcium and magnesium, which makes the underlying soil
and water mildly acidic. Since bacteria and fungi find those
conditions inhospitable, the dead vegetation decomposes at a phenomenally slow rate.
Instead of breaking down right away, it lingers piling up.
Over time, masses of the botanical waste gradually turn into peat,

(01:49):
a soggy, mud colored substance. Peat can be used as
animal bedding and as a fossil fuel, which makes it
an important commodity in places like the Irish Midlands and
in Scotland, where it's the traditional fuel for fires that
dry out grain to make Scotch whiskey, imparting smoke and
its flavors along with that heat. But to archaeologists, pete
is a lot less valuable than the human corpses that

(02:10):
sometimes come with it. Bogs have long fascinated humans, not
just for their fossil fuels. The spongy soil has intrigued
people as far back as the Bronze Age. Many people
died in these bogs or were placed there after their deaths,
and these bog bodies, as theirre known, have been found
all over the world. The wetlands of northwestern Europe, for instance,
is a bog body hub. Hundreds of these corpses have

(02:33):
turned up in Germany, England, the Netherlands, and neighboring countries.
In twenty eleven, pete harvesters working in Ireland accidentally ran
over a Bronze Age corpse with a milling machine. Dubbed
the cashle Man. The harvester found all that was left
of an adult male who probably died in his twenties.
His body was riddled with injuries, including a broken arm
and a nasty cut across the backside. Some of these

(02:55):
may have been caused by the compressing weight of the
bog moss above him or the blades of that milling device. Nevertheless,
archaeologists have reason to suspect that the casual Man was
a ritualized sacrifice victim. Other European bog bodies have displayed
stab wounds, slit throats, and evidence of torture. Historians think
that the local wetlands were once a hotbed for religious sacrifices.

(03:17):
Carbon dating tells us the casual Man perished about four
thousand years ago, seven centuries before King Tuton Common was born.
To date, he's the oldest European bog body on record
with intact skin. That's right, the corpse of somebody who's
been dead for four millennia still has its skin attached.
And this isn't a fluke. Lots of bog bodies retain
some or all of their original skin. The talland Man,

(03:40):
a twenty three hundred year old corpse recovered from a
Denmark peat bog in nineteen fifty, has skeletonized hands, but
elsewhere his skin is so well preserved that little details
like the wrinkles on his forehead are still visible. Although
the talland Man's skin didn't rot away, the mummification process
did change its appearance and texture. Like the man and
lots of other bog bodies, he sports leathery, dark brown skin.

(04:04):
Some of them also have preserved hair that was dyed
red after death. This is most likely caused by a
recently discovered polymer called sphagnin, which seeps out of dead
sphagnum moss if you think of leather. It's made through
a process called tanning that strengthens the bonds between some
of the natural fibers in animal hides. As a tanning agent,
sphagnin has the same effect on human skin, rendering it

(04:26):
tough and tea colored. Sphagnin also binds with nitrogen, which
bacteria need to survive, so by removing nitrogen from the environment,
spagnin helps prevent the spread of microorganisms that would normally
be breaking down human and animal remains. And Furthermore, sphagnin,
along with the acid that it turns into, pulls calcium
right out of dead bodies. Bones get weakened in the process.

(04:50):
Although spagnin does a fine job of preserving skin, its
calcium thievery isn't great for skeletons. Mummies have been found
in certain bogs with soft, extra flimsy bones that are
about Astarte's cardboard and that have been distorted by heavy peat.
But that's assuming the decalcification process doesn't altogether eliminate bones.
Lots of bog bodies have been found missing bones, and

(05:11):
some of the mummies are totally boneless. The latter are
basically human shaped bags of leathery skin wrapped around some
pickled organs. Not all bogs are so hostile to bones, though.
The water's acidity level varies from bog to bog, and
this impacts corpse preservation. Archaeologists have discovered that in really
acidic peat bogs, the resident mummies have lots of skin

(05:32):
and soft tissue and weak or non existent bones. But
there are some boggy places with relatively alkaline water. Here
the environment pretty much has the opposite effect on corpses.
A take, for example, the wind Over Archaeological Site, a
peat bottomed pond in Florida that became the final resting
place for dozens of Native Americans between seven and eight
thousand years ago. Skeletal remains from one hundred and sixty

(05:55):
eight people have turned up in the peat. A large
deposit of crushed up snail shells lying to the pond
supplies the water with magnesium and calcium carbonates that makes
the water more alkaline, neutralizing the sphagnen to an extent.
Instead of mummified skin bags the bog is rife with
naked bones and skeletons a bear as they are on
the outside, the ancient bones had a big surprise in

(06:17):
store for scientists. Brain tissue was found in more than
ninety of the windover pond skulls, making them extra fascinating
fines by the way bonus fact of the episode. Most
carnivorous plants, such as sundews and pitcher plants grow in
bog soils, which tend to be nutrient poor. Eating animal
prey is a strategy that helps them obtain vital nutrients.

(06:43):
Today's episode is based on the article peat bogs are
freakishly good of preserving human remains on how stuffworks dot Com.
Written by Mark Mancini. Brain Stuff its production of I
Heart Radio in partnership with house stuffworks dot Com and
is produced by Tyler Klain. For more podcasts my heart Radio,
visit the iHeartRadio app, Apple podcast Guests, or wherever you
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