The process of fossilisation is exceedingly rare and finding a fossil that reveals exactly how an individual died is even rarer.
What is a fossil?
A fossil is simply the preserved remains, impression, or trace of an animal/plant from a past geological age. They’re typically found in rocks, though some are preserved in other materials such as amber.
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For a fossil to form, a number of different conditions need to be met but the most important is that hard parts of an animal/plant (e.g. bones, shells, wood) are rapidly buried in sediment, preventing them from decomposing and/or being scavenged.
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Some fossils paint somewhat pleasant pictures, ones where animals have died (seemingly) peacefully as they slept. Others, however, hint at a more grisly end for the individual in question…
10 gruesome deaths preserved as fossils
‘Fighting Dinosaurs'
The ‘Fighting Dinosaurs’ is one of the most famous fossils ever found and preserves a Protoceratops andrewsi (a distant relative of Triceratops) and a Velociraptor mongoliensis (the antagonist of the original Jurassic Park) embroiled in a death match.
The fossil was found in 1971 at a site known as Tugriken Shire, located in southern Mongolia and deep in the heart of the Gobi Desert. It has been dated to around 75 million years ago and serves as one of the best examples of predatory (or at least antagonistic) behaviour in dinosaurs.
Despite the fossil’s incredible level of preservation, it’s unclear in what order, and most importantly how, the animals died. The timing of the individuals’ deaths has been the source of much debate, with some suggesting the Velociraptor was scavenging an already-dead Protoceratops at the time of its own untimely death, and others that they died simultaneously.
The majority of evidence points towards the latter scenario being the most likely, but what exactly interrupted them mid-fight is a mystery. A number of different ‘killing events’ have been put forward, including: drowned in a lake after tumbling in, entombed by a collapsing sand dune, and/or suffocated in a particularly violent sandstorm.
Whatever ultimately killed the ‘Fighting Dinosaurs’, their brawl was so legendary that it’s still discussed today, 75 million years later.
Fish fight
149 million years ago during the Late Jurassic, there lived a small, ray-finned fish known as Leptolepides. This herring-sized fish was the favoured prey of an aerial predator known as Rhamphorhynchus - a long-tailed pterosaur with a wingspan that is estimated to have measured roughly 2m across.
The two animals are often found in association with one another, but in one particular limestone slab found in the world-famous Solnhofen beds in Bavaria, Germany, a complete Rhamphorhynchus has been preserved with a Leptolepides halfway down its throat.
Only the two animals aren’t alone, there’s a third animal preserved in this chaotic-looking, prehistoric tapestry - a larger, 1m-long fish known as Aspidorhynchus whose pointed jaws have pierced straight through the Rhamphorhynchus’ leathery wing.
This fossil paints a bizarre picture, one where two predators (Rhamphorhynchus and Aspidorhynchus) were targeting the same prey (Leptolepides) and, in the process of the hunt, found themselves entangled.
It’s thought the pterosaur drowned shortly after it became stuck in the jaws of the larger fish. The Aspidorhynchus, on the other hand, likely lived a little longer, but from the weight of a Rhamphorhynchus in its mouth it would have soon sank to the anoxic bottom layers of the lake that it lived in, where it ultimately suffocated from a lack of oxygen.
Duel to the death
While curved, mammoths’ tusks were designed in a way that meant sparring individuals would have been able to untangle themselves with just a few twists. However, if a situation arose where two individuals with oddly-shaped or broken tusks met head-to-head, they may have found themselves in a rather sticky situation and, quite literally, locked in a ‘duel to the death’.
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This is exactly what happened to a pair of Columbian mammoths discovered in 1962 at a site in Nebraska’s Badlands National Park. One mammoth has a complete right tusk but a snapped left tusk, whereas the other has a complete left tusk but a broken right tusk. The blunt and rounded edges of these tusks are signs of healing and suggest the tusks were damaged long before the two mammoths met.
The unusual shape of their tusks meant the mammoths were able to move in closer during their duel, so close even that the tip of one mammoth’s tusk was able to pierce the eye of the other. This closeness resulted in a tanglement that was impossible to reverse - after lots of toing and froing, it’s thought one mammoth ultimately collapsed due to exhaustion, dragging the other down with it.
It wasn’t until after the two mammoths had been completely excavated that a third victim of this ‘duel to the death’ was discovered - a coyote whose skull was found crushed underneath the front leg of one of the mammoths.
That was a low blow
Before T.rex and Triceratops appeared and became bitter enemies in the Late Cretaceous, there was another dinosaur rivalry that was just as fierce, if not even more so. The combatants in this particular matchup were T.rex’s distant relative Allosaurus and the famous, plate-backed herbivore Stegosaurus.
Both Allosaurus and Stegosaurus lived in North America during the Late Jurassic (155 to 143 million years ago) and shared similar habitats, such as flat floodplains and forest margins.
There’s evidence to suggest the two dinosaurs regularly battled: an Allosaurus tail vertebra with a partially healed puncture wound likely inflicted by a Stegosaurus’ tail spike and a Stegosaurusneck plate covered in Allosaurus-shaped tooth marks are just two examples of such hostile interactions.
However, the fossil that captures the most gruesome bout between these two titans is an Allosaurus pubic bone that bears a huge, circular hole, understood to have been made by a Stegosaurus’ tail spike as it slammed into the crotch of its rival.
The Allosaurus in question didn’t immediately die as a result of this low blow; instead, signs of a fist-sized abscess next to the hole suggest the wound became infected and that the once ferocious predator spent the next few weeks limping and expelling litres of pus before it eventually succumbed to a fatal condition like sepsis.
The mammal that took on dinosaurs three times its size
During the time of the dinosaurs, mammals were small and lived predominantly nocturnal lifestyles, only venturing out at night once most dinosaurs were asleep. Most were likely viewed as prey, though there was one badger-sized mammal that may have caused some dinosaurs to think twice before approaching it - Repenomamus.
Repenomamus lived during the Early Cretaceous (about 124 million years ago) and was by the far the largest mammal of its time. The only Mesozoic mammal that may have exceeded it in terms of size is the Late Cretaceous-aged Patagomaia, which may have been as large as a small dog.
Repenomamus has somewhat of a belligerent reputation, largely as a result of a single fossil discovered recently at a site in Liaoning, northeastern China. This fossil preserves a Repenomamus wrestling with an adult Psittacosaurus more than three times its size.
Given that the Repenomamus’ claws were found tightly gripping the head and lower body of the Psittacosaurus, researchers are pretty confident that it was actively preying on the herbivorous dinosaur and not just scavenging a carcass.
However, this predation attempt proved to be poorly timed. Like the ‘Fighting Dinosaurs’ discussed above, the Repenomamus and Psittacosaurus are preserved in a fighting position, suggesting they were rapidly buried. Signs of a nearby volcanic eruption have led researchers to suggest they were probably covered by a layer of burning-hot debris as they fought.
Choked on a fish
The saying ‘don’t bite off more than you can chew’ not only has a metaphorical application, but a literal one too. Clearly this message wasn’t understood by a 200-million-year-old, squid-like creature known as Clarkeiteuthis montefiorei that died with a sardine-sized fish (Dorsetichthys benchi) lodged in its jaws
The fossil of this 20cm-long, soft-bodied predator was found way back in the 19th century on southern England’s famous Jurassic Coast, but it wasn’t until it was re-examined in a 2020 study that the individual’s gruesome fate was finally revealed.
The fish, whose skull has been crushed by the Clarkeiteuthis’ sharp beak, is halfway swallowed and its body is surrounded by many small, tooth-shaped hooks - signs that it was also enveloped by the Clarkeiteuthis’ arms.
Based on this prehistoric crime scene, researchers have come up with two potential theories as to how the individuals may have been preserved together.
The first is that the fish was simply too large for the Clarkeiteuthis to swallow and, in attempting to do so, it ultimately choked to death. The second is that it grabbed its prey in its jaws before swimming down to the seafloor in order to avoid its catch being stolen by another predator. However, by doing this it may have inadvertently swam into bottom waters low in oxygen and suffocated.
Death from above
In 1924, the fossilised skull of a young hominid was discovered by quarry workers at a site in Taung, South Africa. This specimen was nicknamed the Taung Child and it’s so well preserved that it informed the description of a new species the following year, Australopithecus africanus.
As well as being taxonomically informative, the Taung Child also shows signs of having been preyed upon, suggesting that - 2.8 million years ago - our ancestors were still a long way from the top of the food chain.
Ditsong National Museum of Natural History, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
In the Taung Child’s eye sockets, there are puncture marks that match those made by the talons of eagles on living primates. There’s also a depression along the top and back of the skull that’s indicative of an attack by an eagle.
It’s unknown exactly what kind of eagle grabbed and carried away this young Australopithecus, though some have suggested it may have been an ancestor of today’s crowned eagles.
These eagles are far from the largest eagles alive today, let alone during prehistory, but they are widely regarded as one of the most powerful relative to their body size and have been known to prey on animals weighing up to 30kg. There are also reports of crowned eagles actively preying on children in some parts of sub-Saharan Africa.
Worker’s dispute
If you thought humans have been going at one another’s throats for a long time, just look at ants for a moment - we’ve evidence of them warring for nearly 100 million years!
In a piece of amber found in the Hukawng Valley in northern Myanmar and dated to the Middle Cretaceous, two worker ants of different species have been preserved in a fight to the death. One of these ants can be seen sinking its pincers into the other’s head - a clear sign that it had the upper hand before the pair were encased in a sticky glob of tree resin.
This is the oldest evidence we have of warring ants and it suggests that different species - as well as different colonies of the same species - often clashed over food and territory, just like they do today.
In other pieces of amber found in the Hukawng Valley, ants have been found within arm’s reach of their modern rivals, termites. This suggests the two groups have a long and bloody history and that their intense rivalry may have started much earlier than first thought.
Trapped in a dinosaur-made bog
In the early 2000s in northwest China’s remote Xinjiang region, several pits containing the remains of dozens of small dinosaurs were discovered. The dinosaurs found in these pits include Guanlong, a feathered theropod whose head is adorned with a mohawk-like crest, and Limusaurus, another small and slender, meat-eating theropod.
The rocks these dinosaurs are found in - a mixture of volcanic mudstones and sandstones - suggest they lived in an environment that had recently been covered by debris ejected by a nearby volcano. This debris likely created semi-solid surfaces over pockets of liquified volcanic mud that may have behaved like quicksand.
Guanlong and Limusaurus were probably light enough to walk across this semi-solid surface unhindered, so why are their remains found trapped in these volcanic mudstones? In a 2010 study, researchers pointed to the size and shape of the pits and suggested that they may have been made by a giant, long-necked dinosaur known as Mamenchisaurus.
As Mamenchisaurus walked and planted its huge, circular feet, it may have broken through the semi-solid surface and exposed the volcanic mud underneath, creating pitfall traps for any trailing dinosaurs.
Mamenchisaurus would have had no trouble escaping the mud; it was giant and had four powerful legs that it could, essentially, put into four-wheel drive. The small, bipedal theropods weren’t so well equipped and as soon as one found itself trapped, others likely followed as they attempted to scavenge its rotting carcass.
Nowhere to run
As far as gruesome, prehistoric deaths go, none are worse than the death experienced by a Homo habilis known as OH 7.
This individual was discovered in 1960 in Olduvai Gorge, Tanzania, and has been dated to ~1.75 million years ago. The remains of OH 7 include fragments of a skull and jaw, as well as several disarticulated leg bones that some think may belong to the same individual.
These remains bear tooth marks that are, interestingly, indicative of two different types of predators. The punctures on OH 7’s leg bones are thought to have been made by a crocodile, while the gouges on the fragments of skull share a lot of similarities with those made by leopards on modern primates.
It has been suggested that one predator may have killed OH 7 while the other later scavenged its carcass. However, the crocodile-inflicted bite marks are only found on one leg and the damage inflicted to the skull was in a spot often associated with predatory behaviour from leopards, suggesting OH 7 may have been attacked by both predators simultaneously.
This paints a particularly grisly picture, one where OH 7 may have had its leg grabbed by a crocodile as it knelt down for a drink at a waterhole, only to then find its head pulled in the opposite direction by a leopard that had just pounced from the nearby bushes.
You don’t need to know that the bite marks show no signs of healing to work out that OH 7 didn’t survive this deadly encounter.
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