The Fossilisation Process

When a land dwelling vertebrate dies its carcass is commonly disarticulated, this means its limbs are removed, often by predators and scavengers alike. Most of the decomposition of the organic material is done by bacteria that will feast on the rotting flesh that remains on the bones. Some bones are completely stripped clean of flesh and bleached in the sun. Others might be carried off or gnawed by rodents. Sometimes, disarticulated remains are trampled and scattered by herds of animals.


Sooner or later the bones are either destroyed or buried. If they aren’t digested their destruction can come from weathering; this is when the minerals in the bone begin to break down and the bones disintegrate. But the weathering can be stopped by rapid burial, it’s at this point fossils are formed. A body fossil is part of an organism that is buried and a trace fossil is an impression left behind in the ground by the organism.


Bone is made out of calcium-sodium hydroxyl apatite, this mineral weathers easily, this means that the mineral is no longer present once a bone becomes fossilised. This mineralogy can remain intact if the bone doe not come into contact with any fluids during its burial, something that is extremely rare.

It is possible to find tissues of extinct animals. Since bones are porous, the spaces once occupied by blood vessels and nerves fill up with minerals. This is called permineralisation.

Fossil of Archaeopteryx. Image credit Humboldt
Museum Fur Naturkunde Berlin

Pristine fossils can be found in geological lagerstatte, feathers of dinosaurs are known from these lagerstatte. Most famously the early bird Archaeopteryx is known from the Solnhofen lagerstatte in Germany.

Ammonite shells are originally made of aragonite, this is unstable so when fossilisation begins the aragonite becomes the more stable calcite. This calcite creates a cast of the shell and this is what we find today.

Woolly Mammoths and Woolly Rhinos have been discovered mummified in the permafrost in Siberia and Alaska. Soft tissue of a Tyrannosaurus Rex has even been found which allowed palaeontologists to see that the animal was female, within the fossil, red blood cells and connective tissues were found.

Natural mummies have been found in a variety of locations around the world; bog deposits or tar pits, deep inside caves, glacier ice and in the permafrost of Alaska and Siberia. A Woolly Rhinoceros was found mummified after it was covered in salty ground water that essentially pickled the carcass, preventing bacteria and microorganisms digesting the flesh by altering the pH of the environment which means that microorganisms cannot survive in these acidic conditions.

Mummified dinosaurs have been found, good examples of these mummies come from Brachylophosaurus and Edmontosaurus. Leonardo, the Brachylophosaurus that features in the palaeoart post, had skin impressions, muscle impressions that showed an excess of tissue around the neck, even parasites are found on Leonardo.


The permafrost is also effective as the low temperature prevents the bacteria from respiring by removing any moisture on the carcass through freezing. However, once the mummy is excavated the bacteria become active and decomposition begins.

Buttercup the Mammoth

Natural mummies have been found in a variety of locations around the world; bog deposits or tar pits, deep inside caves, glacier ice and in the permafrost of Alaska and Siberia. A Woolly Rhinoceros was found mummified after it was covered in salty ground water that essentially pickled the carcass, preventing bacteria and microorganisms digesting the flesh by altering the pH of the environment which means that microorganisms cannot survive in these acidic conditions.


The permafrost is also effective as the low temperature prevents the bacteria from respiring by removing any moisture on the carcass through freezing. However, once the mummy is excavated the bacteria become active and decomposition begins.


In May 2013, scientists from the Siberian North-eastern Federal University took an expedition to Maly Lyakhovsky, an island in the far north of Siberia, whilst acting on information that there was a Mammoth in the permafrost. Indeed they did find two tusks exposed and as they excavated the animal they found that it also had three legs intact, most of the body and part of the head and trunk was still attached as well.

Buttercup the Mammoth mummy. Image credit techentice.com

During the excavation, the carcass released a dark red liquid. The carcass still had fresh blood inside it, this was unique as mummies have only yielded dry specks of blood containing no complete DNA.


The researchers took the Mammoth, nicknamed Buttercup, to Yakutsk where a group of experts were to study the specimen for three days before the find was refrozen to prevent rotting. Carbon dating shows that the Mammoth lived around 40,000 years ago, tests on the animal’s teeth reveals that it died between the age of 50 and 60.


Faeces and bacteria in the lower intestines of the animal, reveal a diet of ice age grasses, buttercups and dandelions. Tooth marks on the Mammoth’s bones enabled the scientists to determine how she died, she was eaten alive by predators after becoming trapped in the peat bog that had assisted in her mummification.


More blood was found in the Mammoth’s elbow, analysis of this blood showed that the cells were broken, but some still contained haemoglobin, the protein that carries oxygen within the red blood cell. Unlike humans, the Mammoths had evolved haemoglobin that was more resistant to freezing temperatures.

Could We? Should We?

I want to discuss the woolly mammoth, Mammuthus primigenius. The mummified remains of calves in the Siberian permafrost have given us a window, from which we can gaze into the world of the Pleistocene.

In 2014, a 28,000 year old mammoth was discovered in Siberia. This mummy was preserved to a high degree with blood, organs, tissues even the animal's last meal was still present. With this discovery and others like it, it has been possible to sequence the genome of a woolly mammoth. But should we clone this extinct beast?

Many people that I talk to simply say 'it would be good to see a live one' and that 'it would be helpful to study'. These are not compelling arguments to bring this animal to life. Yes seeing it would be spectacular, these were magnificent creatures, but they went extinct for a reason, they could not cope in the rapidly changing world. To study them would also be interesting, to look at the way they interact with the world and each other, to give us a true insight into the way they lived, but this would mean having to constantly harrass the mammoth.

A painting of Woolly Mammoths migrating through France near the RIver Somme.
Mammoths would have migrated vast distances with a changing climate in search of food, something
that would be impossible today. Painting by Charles R. Knight.

To even bring this animal to life a surrogate is required. The closest relative is the Indian Elephant. It is unknown what being a surrogate to a prehistoric animal would do to a modern elephant, not to mention the stress. The procedure may not be successful the first time so a number of elephants would have to be put through the procedure to get a result. Ethically we cannot stand for that.

Ecologically the mammoth would not fit in. Since the extinction of the mammoths 10,000 years ago, the world has changed greatly. We no longer have the correct sedges and grasses that the mammoths fed on. The mammoths lived in a habitat called the Mammoth Steppe which stretched right across Europe and into Asia, this has long disappeared, there is not the massive fluctations between glacial and interglacial environments in the present day. Also mammoths migrated great distances during the Pleistocene, from Britain to the South of France, this would be impossible now as the climate is warmer and there is no land bridge between Britain and France anymore.

We have to take humans into consideration here. We are a species that kill for sport and for trophies, unnecessary killings for no gain. Could we trust the minority that hunt animals like elephants, rhinos and lions to leave the mammoths in peace? At the start of 2016 we pushed the Northern White Rhino to extinction, a whole species has disappeared because of us. The Rhino isn't alone on the list, we've been responsible for numerous extinctions due to hunting, destruction of habitats and pollution. Even if the mammoth survived the human race it wouldn't be long until they are locked away in zoos for our entertainment rather than being allowed to roam the wild. The atmosphere is polluted a great deal more than in the Pleistocene, small environmental changes are partly responsible for the extinction of the mammoth so I don't believe a resurrected one will survive for very long with the environment in the state that it is in today.

Dr Victoria Herridge, who performed an autopsy on the young mammoth in 2014, wrote in The Guardian saying that it 'would be ethically flawed' and that she is yet to hear a convincing argument that supports the cloning of the mammoth.

Personally, we should stop here, we know we have the capacity to do it, we don't need to prove we can do it.

What are your opinions on this matter? Would a mammoth herd fit into our world? Let me know in the comments.