Digitising Darwin’s Fossil Mammals


In the latest update to the digitisation of Darwin’s fossil mammals project, we have produced a new 3D model of the very first specimen of Mylodon darwinii found by Charles Darwin on the Voyage of the Beagle.

Researchers have 3D surface scanned the lower part of the jaw belonging to Mylodon darwinii and released the digital specimen online to celebrate Charles Darwin’s 210th birthday. On finding the specimen Darwin correctly identified it as belonging to the same family as the modern sloths. We hope that by sharing this digital resource more people can access and use these specimens.

See Darwin's fossils in 3D

Rotate, zoom in and explore the features of MylodonMegatherium and Toxodon fossils from Darwin's collection.

Darwin's fossil mammals

We are in the pilot stage of an exciting project to digitise the historic fossil mammals collected by Charles Darwin on the Voyage of the Beagle.

Find out more in Adrian Lister's new book.

25 years before he published his theory of evolution through natural selection, a young Charles Darwin was on the voyage of a lifetime. Darwin was confronted with evidence of changes in the distribution and composition of species, of extinction, and of geological and environmental change on a grand scale. His experiences aboard the H.M.S. Beagle between 1831 and 1836 laid the foundation for his future scientific work, culminating in his publication of his theory of evolution in 1859. 

Among the thousands of plant, animal, rock and fossil specimens Darwin collected while aboard the Beagle, he collected 13 species of fossil mammals. These specimens held a special place in Darwin’s heart and mind, demonstrated by his enthusiasm when in the field and their place in his thoughts many years later.

The fossil mammal specimens collected by Darwin on the Beagle have had a complex history.

Collected between 1832 and 1834, they were sent back to England on a series of cargoes negotiated with locals at various ports in South America. On arrival in England they were forwarded on to the Royal College of Surgeons in London. There the specimens, which were still enclosed in their surrounding rock matrix, were prepared.

At the college was the outstanding naturalist Richard Owen, who would later be the driving force behind the creation of the Natural History Museum. Owen studied the fossils between 1838-1840, describing extinct mammal species that were previously unknown.

Retracing history

This project has involved trying to trace each potential fossil mammal specimen collected by Darwin on the Voyage of the Beagle from his field notes to the present day.

As there is no comprehensive list of the fossil mammal specimens collected by Darwin, researchers have had to rely on a combination of:

  • Darwin’s field notes and later publications
  • specimens described by Richard Owen and attributed to Darwin
  • ones listed in the Royal College of Surgeons 1845 and 1884 catalogues
  • specimens still in existence in the present day

During the research, it has become clear that many original specimens are missing.

In an attempt to try every possibility to trace them, in 2016 we contacted Down House, the home of Darwin. To our surprise, we received a positive response: they had a specimen in their collections which was labelled as a fossil mammal. A visit confirmed that it was the other half of a specimen in the collections of the Royal College of Surgeons. You can read about this discovery in this Royal Society blogpost.

Megatherium reconstruction by Mauricio Anton

In 2018 we had the privilege of bringing all of the remaining fossil mammal specimens collected by Darwin together in one building for the first time since 1843. We scanned the two halves of the Megatherium skull held by the two institutions (Down House/English Heritage and the Royal College of Surgeons). The original specimen has been digitally reconstructed from the two halves and can be seen in the video at the top of this page.

Our aim is to fully document, research, conserve and digitise these scientifically and historically significant specimens and to make the specimens and their stories publically available.

The Museum has undertaken a pilot study to investigate the potential that digitisation holds for this collection. It focuses on 20 fossil mammal specimens collected by Darwin, which have been attributed to Megatherium, Mylodon and Toxodon.

artist illustration of Mylodon by Mauricio Anton

Mylodon reconstruction by Mauricio Anton


Mylodon darwinii is the scientific name for a species of extinct giant ground sloth. It was described as a new species by Richard Owen who named it in honour of it’s discoverer.

Megatherium americanum is the scientific name for an extinct species of giant ground sloth. Its name means ‘great beast from America’. 


Toxodon reconstruction by Mauricio Anton 

Toxodon is an extinct mammal from South America. The word 'toxodon' means 'bow-tooth', from the curved form of the teeth,  and 'platensis' refers to the district (La Plata) near where its remains were first discovered.

Imaging the specimens

The specimens range in size from one centimetre to one metre and include specimens which are challenging to faithfully reproduce using 3D laser scans (due to uneven surfaces with lots of holes). This made them ideal candidates to test the technology. 

Photograph of  a Toxodon Specimen being scanned with the laser scanner

 Megatherium specimen being scanned with the laser scanner

An arm-mounted laser scanner captured the profile of the surface, including any cracks, peaks, troughs and texture. The initial capture of the data was completed in a few days. The next step involved processing the data, which took around five times longer.

This complex surface is difficult to capture and reproduce. In the end though, this intricate model will provide just as much detail as its real counterpart.

Digital teams are interested in experimenting with virtual reconstruction techniques to understand how 3D imaging can bring these specimens to new audiences and inspire curiosity about the specimens that were crucial to Darwin’s theories.

You can check out the Darwin Fossil Mammal dataset on the Museum’s data portal or check out the models on Sketchfab. If you have ideas about how you would like to use these models, please get in touch via @NHM_Digitse@NHMFossilMammal and @NHM_IAC on Twitter. 

Project summary

  • Focus: Digitisation and conservation of Darwin's fossil mammals. This will include trialing new workflows and outreach methods.
  • Funding:  Hartnett Conservation Trust / Leche Trust / Barbara Whatmore / Charles Hayward Foundation
  • Start date: November 2017

Project team

  • Pip Brewer
  • Adrian Lister
  • Jennifer Pullar
  • Amy Scott-Murray
  • Richard Fariña
  • Sebastián Tambusso
  • Luciano Varela
  • Kate Burton
  • Emily Keeble
  • Lucia Petrera

    With assistance from 

  • Lu Allington-Jones
  • Brett Clark
  • Roula Pappa

Digital collections blog

Catch up with the latest digitisation techniques and technology.

Related information

The data from this project is freely and openly available to researchers around the world via the Museum's data portal.