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We tend to think of fossils as dinosaur bones or petrified wood, but what if we told you that there's a lot we can learn from fossilized waste?

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Bird vomit: News article about Wang et al 2016 (full disclosure, I wrote this article)



Worm sperm:


Dinosaur pee:

Image Contacts:
As Alyssa requested, some contact info for scientists you might be able to reach out to for images (many are simply the authors of the relevant studies).

Bird vomit:
I’ve corresponded in the past with the first and third authors of that study, so I know they should both be good contacts:
Min Wang:
(Dr. Wang provided the images used in the popular article on Earth Touch News)
Corwin Sullivan:

Fossil brooding balls: Dr. Krell studies scarab beetles, and is an author of the publication with all these lovely photos: Karen Chin is the “Coprolite Queen” – I bet she could provide photos or point you in the right direction All of these authors also have email addresses listed. They are all in Argentina.

Amber farts:
George Poinar Jr. is the author of the book chapter I referenced above.

Worm sperm:
First and senior authors of the study:
Benjamin Bomfleur
Stephen McLoughlin

Fossil ambergris:
First author of the study: Angela Baldanza
Other author emails are all listed. All are in Italy;;;;

The two famous urolite publications (the ones mentioned in the Nat Geo article) were first-authored by these two:
Katherine Mccarville:
Marcelo Adorna Fernandes

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The geological record of our planet has been collecting fossils for billions of years and it has given us some incredible ancient remains.  Most of the world's most famous fossils are what paleontologists call 'body fossils', the remains of an organism's body.  Dinosaur bones, tree leaves, even fossilized bacterial cells, these are all body fossils, but there are also trace fossils, remains of things that organisms left behind.  These can include footprints, burrows, and even waste.  We all make it!

Dropping off unwanted bodily secretions is an animal tradition going back hundreds of millions of years and with the right burial conditions, it can produce fossils that are truly amazing, if a little, you know, gross.  So here are six of the most extraordinary examples of ancient excrement.

 1: The World's Oldest Bird Vomit (1:00)

Around 120 million years ago, a bird living in what is now China ate a bunch of fish, digested the meat, and then puked up those bony leftovers.  Now, most vomit blobs like this probably decomposed pretty quickly, but lucky us, this one was buried and fossilized along with the body of the bird that barfed it.  It's one of the oldest known bird gastric pellets and if you think the idea sounds familiar, that's because birds still do this today.  If you've ever dug into an owl pellet in science class, you've seen one example of the modern-day version.

In today's birds, the stomach has a special chamber called the gizzard.  There, food is liquefied so it can be sent on to the intestines, but all the hard, indigestible stuff like bones or shells are collected and sent back up the throat and voila, a pellet is puked.  Finding a pellet full of fish bones not only tells us what this fossil bird had for lunch, but it also teaches us something about bird evolution.  

You see, this ancient puker wasn't a modern-style bird.  It belonged to an extinct group called the enantiornithes.  

 (02:00) to (04:00)

These were bizarre birds by today's standards, at least.  Most of them had teeth in their beaks and claws on their wings, but that ancient vomit is evidence that these birds had a digestive tract like modern birds, complete with a gizzard for collecting bones and an esophagus capable of pushing up pellets. In fact, similar pellets have been found alongside dinosaurs closely related to birds, which suggests to scientists that this avian digestive system had already evolved in the earliest bird ancestors.

Also, here's a bonus, paleontologists were even able to identify the bones in the pellet.  They came from an ancient fish called lycoptera.  All that from a barfed up ball of bones.

 2: Ancient Poop Nurseries (2:41)

As we all know, everyone poops and that includes ancient creatures.  Fossilized feces, called coprolites, are a paleontological favorite.  They can teach us about ancient animals' diets, digestion, and even their gut parasites, but one type of coprolite in particular is notable for what got into the poop after it came out of the animal.

They're called coprinisphaera, named for their sphere-like shape, and they were built by ancient dung beetles.  Dung beetles are famous for their habit of rolling around balls of poop, but they're not doing that just for fun.  Often, they're using the dung as a brooding ball.  Mama beetle lays her eggs inside and when they hatch, the larva are born into a big ball of breakfast.

Fossilized brooding balls can be found in many shapes and sizes, dating back as far as 60 million years or more.  They're a great tool for studying when and where dung beetles have lived throughout time and how they took care of their young.  There's even at least one case of a fossilized beetle preserved inside of its dung ball.  Incredibly, some fossil brooding balls are so well preserved that paleontologists can still see tunnels and chambers inside where the beetles hatched and burrowed around.

Some of these ancient brooding balls even preserve evidence of parasites: flies, bees, and other moochers that set up shop in the dung beetles' hard-built structures.

 (04:00) to (06:00)

 3: Fossilized Farts (4:01)

Then there are the fossilized farts.  I know that it sounds like I'm making that up, but farts can totally become fossilized.  All it takes is really good timing and a little bit of tree sap.  Certain trees produce sticky resin and if that resin is preserved for long enough, it can become amber.  Amber is famous for trapping and preserving plants and insects inside, which is why John Hammond had a chunk of it at the top of his cane in Jurassic Park.  

In real life, amber cannot preserve dino DNA, but it can preserve air bubbles, and isn't that just as good?  And if a trapped insect passes gas at the very right moment, it may leave behind a tell-tale sign of its indiscretion, a bubble trapped forever in the compromising position of emerging from that bug's anus, and you thought your high school yearbook picture was embarrassing.  That bug is farting for millions of years.  Just a million year fart.

As you can imagine, this is pretty rare, but amber farts have been seen in beetles, termites, ants, bees, flies, midges, and cockroaches going back tens of millions of years.  Some of the bubbles might genuinely be the insects' final farts, although they could have also been post-mortem toots produced by microbes still alive inside of them.  In some cases, there will be several bubbles coming out of a bug's butt, possibly from different types of gut microbes, and these fossils aren't just hilarious, though they're definitely hilarious, they can also tell us a bit about what went on inside these insects.

Farts, whether from a human or a termite are often made of the gas produced by microbes that live in our guts, so those fart bubbles trapped in amber are a sign that these ancient insects were home to bacteria, fungi, or other microbes just as they are today.  The gas isn't just a trace fossil from the insect.  It's also a trace fossil from the microbes inside.  It's even been suggested that we might be able to identify what microbes were in these bugs' guts by testing the gas in those bubbles, but it doesn't seem like anybody's tried that just yet.  We're looking out for it. 

 (06:00) to (08:00)

If you happen to have access to some fossil farts in a lab to try and do it yourself, please let us know how it goes.  Alright, so this is kinda cheating because excrement technically refers to waste material but it's awesome enough that we had to put it in the list anyway.  Sperm is an extremely common substance but an extremely rare fossil.  It takes very specific conditions to even have a chance of fossilizing microscopic sex cells.  

 4 :Worm Sperm (6:26)

It turns out, those conditions can be found inside of some tiny worm cocoons that are up to 50 million years old.  These cocoons are actually pretty common in the fossil record.  They're made by a group of worms called clitellates, which includes some familiar faces like earthworms and leeches.  When it's time to make babies, clitellate worms form a hard-shelled cocoon, deposit their eggs and sperm inside, and then crawl off to let the new baby worm develop in its protective casing.

In one 2015 study, when researchers took a close look at fossilized cocoon fragments from Antarctica, they found super tiny leftover remains of spermatozoa, in other words, worm sperm.  Not only is this the oldest known animal sperm in the fossil record, it's also a rare glimpse into the history of these worms.  

Worms, as you can imagine, don't fossilize well, and these cocoons don't usually tell us a lot about the specific type of worm that left them, but different types of clitellate worms can be identified by the shape of their sperm.  These fossil sperm in particular appear to belong to a variety of crayfish worm.  These are worms that make their living as parasites of crayfish.  So these cocoons might be a good place to look for more of these worms and maybe even more of their sperm in the fossil record.  Just think, a whole paleontological specialty, an ancient sperm hunting.

 5: Waxy Whale Chunks (7:45)

If you're walking along the beach and come across a chunk of something greyish and waxy with a pleasant aroma, it might actually be worth picking it up.  You may have found a piece of ambergris.  This stuff is a long sought after ingredient in fine perfumes, so it may be pretty valuable.  

 (08:00) to (10:00)

You may even be able to sell it, and then you might want to wash your hands, because it's some form of whale poop or vomit.  Ambergris comes from the intestines of sperm whales.  Scientists think it forms when indigestible materials like squid beaks cause a congestion in the whale's digestive tract.  This ends up forming a fecal clot that builds and builds, sometimes until it ruptures the whale's guts.  Ambergris can then be found inside the body of the dead whale or floating around in the sea after the whale has died and decomposed, and then humans collect it and spray it on themselves to smell fancy because we are the weirdest ones.

In 2013, paleontologists reported the first examples of fossilized ambergris from a site in Italy dating back to just under 2 million years ago.  They found 25 chunks of this stuff in an area of about 1200 square meters and some of them were huge, more than a meter long.  The scientists were able to identify these as ambergris due to their chemical composition, not to mention the fact that they had fossilized squid beaks inside of them. 

Now, why there are so many bits of ancient ambergris in this one spot is a bit of a mystery.  It might be that this was the location of like, a mass death of sperm whales.  The fossilized bodies of the whales haven't been found, but they did leave behind this graveyard of poop rocks.  

 6: Dinosaur Pee (9:16)

Imagine, if you will, a dinosaur walking up to a (?~9:19) tree, lifting up its leg and, you know where this is going.  If a dinosaur peed against a tree like that, we might never find fossil evidence of it, but if it peed in the sand, then it might leave traces behind like ones found in Sao Paolo, Brazil.  There, in sandstone around 120 million years old, paleontologists have found a variety of dinosaur footprints, along with strange structures that appear to have been made by fluid dropping onto the sand.

To test this hypothesis, the researchers recreated the urination event, although they didn't actually pee, they dumped a bucket of water on to sand from about a meter up, and sure enough, it left behind a very similar trace.  Scientists have dubbed these traces 'urolites'.  

 (10:00) to (11:54)

The urolites found in Brazil can be up to around 30 centimeters long, but similar fossils found in Colorado measure as long as three meters.  Not surprisingly, these enormous pee craters are associated with the footprints of sauropods, the group that includes the largest animals ever to walk the planet.  All this brings up a burning question that has bothered paleontologists for years: did dinosaurs pee?  

The only dinosaurs still alive today are birds, and birds tend to make solid or goopy waste instead of a stream of urine like us proud mammals, but it turns out there are exceptions to this.  Ostriches, for example, sometimes eliminate their liquid waste separately from their solid waste, creating a powerful stream of urine.  Weirdly enough, that's a thing I already knew about ostriches.  In fact, when ostriches pee in the dirt, it leaves behind traces very similar to those urolites, and crocodiles, the closest living cousins of dinosaurs, can also expel liquid pee. 

Remarkably, we still don't know for sure how ancient dinosaurs did their business, but if nothing else, it probably was not a great idea to stand like, directly beneath a big dinosaur.

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