For inducing fear and unease, dead things are big-time spooky. Geological factors can result in recording death in particularly captivating ways, freezing the animals’ death throes across enormous stretches of time. Preservation can mean bones replaced by mineralization to give us skeletal remains, impressions in fine sediment retaining incredible detail, or entire animals trapped in the resin of a tree, that later hardens into a transparent time capsule. Some amazing fossils and preserved carcasses tell us not only how these animals died, but also about how they lived.

Spider with its last meal, preserved in amber.

The earth doesn’t care about us or other life forms on it. Death is part of life and probably shouldn’t freak us out as much as it often seems to. (An example is the hubbub and outrage over the #bestcarcass tag on Twitter, it’s pretty educational. OK, not so “pretty” but still educational.) Remnants of death provide us with extremely valuable information about how an animal LIVED.

And there can be examples of exquisite beauty. This mouse died in a copper mine where the minerals chalcanthite (hydrated copper sulfate) and atacamite (copper chloride hydroxide) crystals have grown on the hair of the carcass like rock candy on string. This specimen belongs to the Fersman Mineralogical museum in Russia.

Mouse encrusted with copper mineral crystals. Fersman Mineralogical Museum, Russia. 

This spectacular fossil (featured on #bestcarcass) shows a fatal encounter between a fish-eating pterosaur and a pterosaur-eating fish. [A small Rhamphorynchus was in the act of swallowing a small fish when it was attacked by a large gar-like fish called Aspidorhynchus. The fish could not swallow the winged reptile for reasons unknown and failed to free itself from the ill-chosen meal.

Rhamphorynchus pterosaur and Aspidorhynchus fish. Fish looks pissed off things turned out this way.

The violent death scene is described by authors Frey & Tischlinger (PLOS One, 2012):

That the fish, in fact, tried to get rid of the pterosaur by vigorous movements of its head is evidenced by the distortion of the left wing finger elements, while the remaining skeleton of the Rhamphorhynchus lies in natural articulation. Apparently, the flight membrane tissue remained jammed between the teeth, while the interphalangeal ligaments of the left wing finger ruptured under the power of the fish tearing at the flight membrane. Finally, the entire wing finger of the drowned pterosaur was pulled under the antebrachium. Such a distortion can only happen when the proximal part of the flight membrane, likely the thin and structurally weak tenopatagium, was dramatically overextended or even had ruptured. The most likely scenario is that the Aspidorhynchus fought its victim for a period of time, thereby rapidly sinking into the hostile anoxic water layer of the Late Jurassic Eichstätt basin, where it was instantly suffocated. Still linked together, both carcasses sank to the sea floor, whereby the pterosaur contacted the ground first, likely being pushed down by the massive head of the Aspidorhynchus.

The fine sediment in this area became the Solnhofen limestone of Bavaria that provided us with many other astounding fossils, including Archaeopteryx.

Another famous fossil that tells a harrowing story is that of Oviraptor (egg-stealer), so named because of this particular fossil that was found associated with a clutch of eggs. Scientists at the time interpreted the dinosaur to be stealing the eggs to eat when the thief and nest were buried and preserved. The more dramatic truth was revealed when it was later confirmed that the eggs belonged to the Oviraptor who was guarding them when death descended upon the brood.

An Oviraptor reconstructed as guarding a nest. By EvaK, CC BY-SA 2.5,

A maternal moment was paused at a critical time as a mother ichthyosaur is forever in labor as she died during birth of her offspring. There are at least two other babies associated with this fossil – one outside and another still unborn. The mother could also have died first and the young were spontaneously aborted. (There are no good pictures of the entire fossil but see another example below.)

Another example of an ichthyosaur that died with a neonate in the birth canal.

Two other carcasses were preserved as evidence of mortal combat. A Velociraptor (predator) and Protoceratops (prey) preserved together show evidence of broken bones. It is unknown if one or both of the animals were alive at burial or recently deceased from their encounter. A similar scene depicts a Nanotyrannus and a Triceratops.

Just like two deer who die with their antlers entangled, a pair of mammoths collapsed head to head with their tusks lodged together. A wolf had been pinned underneath the carcasses.

Mass death

A particularly disturbing scene is that of a mass death. In some cases, the remains will be covered by sediment and preserved. From these incidents, we know that some dinosaurs traveled in herds, like wildebeest. Washed away by a swollen river, their bodies were buried and excavated millions of years later in a mass of bones.

The Hilda mega bone bed in Dinosaur Provincial Park, Alberta, Canada is the location of where a great herd of Centrosaurs died en masse either by trying to cross a raging river, or drowning in a flood [artist’s depiction here]. The dense collection of bones is estimated to be those of 667 individuals killed at the same time. Creationists love this example of mass death attributed to a flood and use it to further their “great world flood” catastrophe. Instead of proof of a Biblical myth, this example shows us that these animals stayed together in these large herd sizes where ages and sizes varied. There are several examples of localized flooding, but in this case, the sediment buried the unfortunate victims of the raging storm.

Catastrophists like Velikovsky and Donnelly pointed out mass bone beds as further evidence of sudden earth events. Fish fossils are found in what appear to have been massive shoals. An Upper Miocene strata in Algeria consisting of deep and shallow water fish and diatoms was interpreted as being the result of a volcanic event (1933, Journal of Geology) An amphibian graveyard in New Mexico may represent the mass death of animals that congregated around the last remaining water in a time of drought (1939, Scientific Monthly and Science News Letter). [1]

Frogs frozen in ice.

Kirkland, et al. (2016) described a mass death assemblage of well-preserved Utahraptors fossils, found in a sandstone sill, that they interpreted as resulting from “quicksand”. The original ground was oversaturated sand possibly fed by artesian springs exerting upward pressure. Small animals could run across it. Large animals that stood on it would become trapped, sinking into the liquid sand burying them deeper and deeper.

A similar situation occurred in another geologically deadly place that gave scientists a comprehensive catalog of past life in an area now completely different – LaBrea Tar Pits in downtown Los Angeles. The pits were a death trap for animals during the Pleistocene who came to drink the water off the surface in the dry climate only to get stuck in the thick sticky ooze welling up from the oil deposits below. The prey animals would be slowed down or trapped by the few inches of natural asphalt springs. Predators would come along and feast. A huge diversity of animals and plants have been recovered from the LaBrea deposits. Animal collections contain thousands of fossils from the same species across all ages. Some have spectacular degrees of preservation such as bones that include fossilized blowfly larva, and plant fragments remaining between the teeth [2]. Smelling of hydrocarbons, with fresh black seeps marked by orange caution cones along the park path, and some of the millions of bones on display, the LaBrea pits remain a spooky place even under the gorgeous California sun.

LaBrea tar pits in downtown Los Angeles. Photo: S. Hill
Sticky tar in shallow ponds can cause heavy animals to become mired. Photo: S. Hill

Twelve million years ago, in Nebraska, horses, camels, and rhinos, adults and babies, perished together in a water hole after volcanic ash billowed in suffocating them. Now designated Ashfall Fossil Beds park, a park official called it “a very graphic display” as some rhinos have unborn young inside.

Ashfall fossil beds preserved great beasts as they fell.

This scene of animal mass death is echoed in one of the most famously preserved human mass death locations – the ancient city of Pompeii, Italy when Mt. Vesuvius buried towns in ash 25 m thick. When the volcano erupted in 79 AD, most townspeople had left. The explosion caused utter darkness and sent searing hot gas, ash fragments, and pulverized rock dust rocketing over land enveloping the escaping residents including mothers, children, pets and livestock. The heat of the surge killed them instantly. The dense, moistureless burial conditions caused imprinting of fine details into the deposit and hid the streets, buildings, and art of the age until they were rediscovered in 1748. A technique called the Fiorelli process was used whereby plaster was poured into cavities in the ash where the bodies had once been before decaying away. The result were the incredibly spooky death poses of those who perished in the cataclysm.

The dog of Pompeii.
Mother and child collapsed when they could not outrun the seething hot cloud from Vesuvius.

The Earth takes away, and sometimes, it gives.


1. W.R. Corliss, Neglected Geological Anomalies, 1990, The Sourcebook Project. p. 86-87.

2. J.M. Harris (ed), Rancho La Brea: Death Trap and Treasure Trove, 2010, Los Angeles County Museum of Natural History Foundation.

1 thought on “Amazing fossils: Death scenes – geologically preserved

  1. Also worth a shout out are fossilised examples of parasitism. Good evidence can be found in amber, but my own favourite is seen in the columnals of my beloved crinoids. All manner of nasties can be seen, a particularly ghoulish one is the parasitic coral cladochonus.

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