A tale of two seahorses

Real or fake? Do replicas have a value of their own? Elaine Charwat is exploring this in her PhD, using the Museum’s large collection of natural history models and casts to research their role in science. Here she tells the story of the fascinating fish that caught her imagination…

By Elaine Charwat

It all started with a seahorse. Last year, I walked into a little seaside shop, and I spotted a seahorse. I instantly flipped back to the happy day I bought my first dried seahorse as a child, the beginning of a life-long passion for the natural world. The man behind the counter smiled: “It’s a fake.” Really? “3D printed.” It looked absolutely perfect. Tracing its lines with my fingers, I said, “It’s a model”.

Ever since I became interested in models and replications, I have encountered this perception of them as “fakes”. Quite recently, I heard the curator of a natural history museum call the cast of a dinosaur skeleton a “fake”. Models in natural history – and in this I include casts and reproductions – are what the Germans call “Wissensdinge”, objects that contain, distribute and generate knowledge. In this aspect, the real specimen and the model meet. Models are made from a vast array of materials with often astonishing skill and technologies. They represent what we know about a particular organism at a certain point in time. They have a history, a context.

Long live the replica! Most of our most beloved dinosaur skeletons in museums are partly or fully casts of bones, like Stan’s here at the Museum. Almost complete skeletons like Stan’s are extremely rare, and casts allow us to share and preserve them. Accompanying models give the bones “flesh and blood” – and provide a snapshot of what was known about the dinosaur when the model was made.

But they are also ambassadors, and this is something I realised when I held the “fake” 3D-printed seahorse in my hand. While it becomes ethically problematic to buy specimens of organisms like seahorses, something of it is captured, and communicated, in a reproduction. I can still trace its exoskeleton, and marvel at its strange symmetry. This symmetry, incidentally, is being analysed for its potential in robotics. Seahorses have unusual tails – instead of the cylindrical trail structure found in most animals, theirs have a square cross-sectional architecture, resulting in a unique combination of toughness and flexibility. In fact, when studying the unique abilities of the seahorse’s tail, researchers have actually used 3D-printed specimens.

Seahorse from the Museum’s collection. Even in Victorian times, long before 3D printers, there seems to have been a desire to emphasise that souvenir seahorses were “natural” – i.e. not man-made. Was it because seahorses are easily preserved and so attractive when dead and dried?

The Oxford University Museum of Natural History has a largely unexplored wealth of models and casts. Many of them date to the second half of the 19th Century, the heyday of their production. Made from glass, wax, metal, wood, plaster, papier-mâché or, indeed, actual bone and feathers, they were modelled, cast, sculpted, glued, painted and mounted to enhance and preserve our understanding and appreciation of nature. But they also tell of scientific discoveries and controversies, research and teaching, rivalries and collaboration, politics and society, ideas and identities.

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Spot the replica – both the specimen and the 3D printed seahorse are “Wissensdinge”, they have a context and provide valuable information.

I will trace these complex relationships in a collaborative and interdisciplinary PhD project called “Nature of Replication”. This is funded by the AHRC and jointly supervised by the Institute of Archaeology, University College London, and the Oxford University Museum of Natural History.

The 3D-printed seahorse now lives alongside my real seahorse. So I like to think of my project as a journey that started with one seahorse, and continues with another.

Bacterial Girl


We couldn’t resist. The moment we came up with the title of our special exhibition, Bacterial World, we were all humming Madonna’s 1985 hit. So here it is – a bacteria-themed version of Material Girl – written, performed and illustrated by the talented Museum team.

In place of “cold hard cash”, you’ll learn that bacteria were involved in the creation of life on Earth, and you’ll find DNA exchange and photosynthesis in place of kisses and hugs. Have a listen… and try to stop yourself dancing.

Of course, you’ll need the full lyrics to sing it in your bedroom with a hairbrush:

BACTERIAL GIRL

Some bugs make you feel unwell
And we’ve all heard of them
But look inside and you will find
That bacteria are your friend

They’ve been around since way back when
In the ocean life began
But nowadays they’re everywhere
So I think you’ll understand, that we are…

Living in a bacterial world
And I am a bacterial girl
You know that we are
Living in a bacterial world
And I am a bacterial girl

They spent some time in the sun
Began to photosynthesise
Put oxygen in the air we breathe
I’m telling you no lies

Now E. coli’s got a real bad rep
For causing people pain
But what you got to realise
Is it’s only one bad strain

’cause we are
Living in a bacterial world
And I am a bacterial girl
You know that we are
Living in a bacterial world
And I am a bacterial girl

Now some bugs love to snuggle up to
Exchange their DNA
Other cells are armed with spears
That wipe enemies away

Resistance to our medicines
You could call it evolution
But microbes might just hold the key
To a medical solution, ’cause we are

Living in a bacterial world
And I am a bacterial girl
You know that we are
Living in a bacterial world
And I am a bacterial girl

You know that we are

Living in a bacterial world
And I am a bacterial girl!

Bacterial World is open until 28 May 2019.

Credits for this little bit of brilliance go to:
Vocals, violin: Laura Ashby
Words, banjo, guitar, recording: Scott Billings
Illustrations: Chris Jarvis

Presenting… Christmas Island

By Eileen Westwig, Collections Manager in the Museum’s Life Collections.

About 320 km south of Java in the Indian Ocean lies Christmas Island. Although discovered and named on Christmas Day in 1643, the island remained unexplored until its first settlement in 1888, a development which had dire consequences for some of its native species.

Christmas Island is home to a variety of endemic animals such as rats, land crabs, butterflies and many birds. The accumulation of bird droppings over thousands of years made the island rich in phosphate, and the commercial potential of these deposits brought many expeditions to the island. With the ships’ cargo came black rats.

Two species of endemic rats, Maclear’s Rat (Rattus macleari) and the Bulldog Rat (Rattus nativitatis) went extinct within 20 years of settlement, despite having been previously very numerous on the island.

One of the skins of Maclear’s Rat (Rattus macleari) collected by H.E. Durham, and now held in the Life Collections of the Oxford University Museum of Natural History.

Maclear’s Rat, seen at the top of the page in an illustration from an 1887 publication, was described as chestnut brown above, with a partly white, long tail. It was once the most numerous mammal on the island ‘occurring in swarms’. The Bulldog Rat had a much shorter tail and a layer of subcutaneous fat up to 2 centimetres thick, the function of which is unknown to this day.

The likely cause of their extinction was the introduction of diseases by the ship rats, to which the Christmas Island rodents had no immunity. The disappearance of the native rats also had a knock-on effect: the parasitic Christmas Island Flea (Xenopsylla nesiotes) depended on the rats as hosts, and so the fleas became extinct with the rats’ demise.

In 1901 Dr. Herbert E. Durham, a British parasitologist investigating the origins of beriberi disease, led an expedition to Christmas Island. During his visit he collected several specimens of Maclear’s Rat, but was unable to find any Bulldog Rats, despite a lengthy search and the offer of a reward. Two of the nine Maclear’s Rats Durham obtained showed abundant parasites, trypanosomes, in their blood.

Christmas Island possesses quite a number of peculiar species in its fauna, and it is regrettable that observations were not made before animals had been imported to this isolated station, as well as that my own notes are so incomplete.

Dr. Herbert E. Durham

Durham also found blood parasites in the native fruit bats (Pteropus melanotus) but noted that these were unlikely to have been introduced, instead were “an old standing native occurrence.” These bats still inhabit various islands in the Indian Ocean, including Christmas Island, where they are critically endangered.

Original letter by H.E. Durham offering his Christmas Island specimens to the Museum in 1938.

The Museum holds a range of material from Christmas Island, including six skins and three skulls of Rattus macleari, which were collected by H. E. Durham in 1901-02, and donated in 1938.

Visit the Museum’s Presenting… case between now and 6 March to see Christmas Island specimens from the collections.

Understanding beeswax

By Tuuli Kasso, PhD in Science Fellow at the Natural History Museum of Denmark, University of Copenhagen. Tuuli is a visiting researcher, who has used the Museum’s collection to help her understanding of beeswax. 

When working on the dissertation for my MSc in Archaeological Science last year, I explored the medieval craftsmanship of sealing wax. I was interested in the way the medieval wax seals had flaked, as the beeswax dried out. Drawing on my previous education in conservation techniques, I began a close investigation of the prestigious material, beeswax.

Medieval craftsmen used a range of dangerous materials to make sealing wax. The red pigment cinnabar, a mercury (II) sulphide, and red lead, are now known to be extremely poisonous.

Although some of the ingredients of sealing wax are very hazardous, there is nothing dangerous in beeswax… except the bees! Produced by honey bees, Apis mellifera, honey and beeswax were important commodities in the Middle Ages. Beekeeping was a skilful profession, housing colonies in woven hives, known as skeps. Colonies were carefully selected to overwinter for the next season.

Manuscript illuminations provide detailed information on the types and construction of beehives in the Middle Ages.England, 13th century. British Library Royal 12 C XIX f. 45.

Beeswax was also important in the Middle Ages for lighting, and beeswax candles were preferred for their pleasant smell. After the Protestant Reformation in the 16th and 17th centuries, the religious use of candles decreased, so demand for beeswax declined.

Even today, the Catholic and Orthodox Churches still require the candles they use to contain a proportion of beeswax.

On my quest to understand the degradation of beeswax in sealing wax and write my disseration, I was very lucky to use some samples from the entomological collections from the Oxford University Museum of Natural History. After some early mornings spent amongst the Westwood collection, I found the perfect specimens of natural honeycombs, from the 19th century. The old hand-written labels were also a lovely encounter when exploring the historical collections.

I compared the samples to modern beeswax and medieval seal samples, and learned that the degradation of beeswax is caused by multiple factors, triggered also by storage conditions. The composition of beeswax is very complex, and there are differences caused by the age of the bee in addition to geographical provenance.

A selection of bee specimens from the Museum’s collection.

The recent catastrophic decline of bee populations has drawn focus to save the bees, and in my PhD research (University of Copenhagen and University of Cambridge) I will explore the recovery of ancient DNA and proteins of bees from beeswax, to cast light on the health of bee populations over time.

Nature’s collectors

by Mark Carnall, Collections Manager in the Life Collections

When giving tours of the invertebrate collections at the Museum, I don’t have much time to cover the considerable diversity of invertebrate animals. When it comes to molluscs (the group including snails, bivalves, squid, octopuses, chitons etc.), which perhaps most people aren’t too excited about, I try to inspire, enthuse and engage with this diverse group by pulling out some of the more weird and wonderful species from the group.

Xenophorids, or Carrier Shells, are up there on the list of weird and wonderful molluscs. Xenophoridae is a small family of around 30 species of marine snails that live on sandy and muddy sea floors in subtropical and tropical seas. So far so snail.

What makes them interesting is that these animals attach objects they encounter to the outside of their shells. The scientific and common name of the group is derived from this behaviour xenos and phoros from Greek translates to “foreign carriers” or “carrier shells”.

This Xenophora pallidula shows a preference for bivalve shells which extend significantly beyond the edges of its shell.
OUMNH.ZC.M3593
Xenophora mekranensis konoi. Top down view of shell, showing bivalve shells and coral fragments attached.
OUMNH.ZC.M3617

Carriers have been found with shells, shell fragments, pebbles, fossils, corals and even shark teeth attached. Predictably human detritus such as coins, bottlecaps and glass and metal fragments have also been found. In this way, they are one of nature’s collectors. Shells preserved in museum collections give us some direct evidence of habitats, environments and preferences of different individuals and species, from the objects affixed to them.

Xenophora cerea going for the rock golem look. The thick cement and attachment site for pebbles which have come off this specimen can be seen at the bottom.
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The mechanisms and evolution of this behaviour are still not well understood and few of the described species have been studied in depth. In species where the process of attachment has been observed, objects are painstakingly manoeuvred to an attachment site by the tentacles, proboscis and foot, the shell surface is then cleaned and the object cemented in place. Generally, objects are deliberately cemented to follow the lines of the shell maintaining an overall cone-shaped shell.

Xenophora neozealanica This individual has gone for a more modest suite of attached objects from sand grains to the discarded spire of another gastropod.
OUMNH.ZC.M3615

There are a number of competing or complementary explanations for why carrier shells attach objects to themselves. This behaviour in molluscs is not unique to Xenophorids, a number of fossils species are known, and some living species in other groups attach things to their shells, but not to the same extent as found in this group.

Perhaps most obviously, this behaviour has been suggested as a form of camouflaging, breaking up the outline of the shell against a sandy sea floor. In some species, long objects attached to the outer whorl of the shell raise it up like stilts, and it’s been suggested that this help to break up a continuous scent trail.

Other suggestions to explain this behaviour include; added armour; predator deterrent; prevention of shells being flipped over and damage to core tissues from shell-borers. It may even increase the surface area in contact with substrate, preventing it from sinking into soft sands or muds.

A trio of Xenophora from the Caribbean, showing the variation in attachment patterns, materials and sizes.
OUMNH.ZC.M3613

Xenophorids aren’t the only animals to ‘collect’ objects from their surroundings. Some of the better known examples are; Bower Birds, which discriminatively collect coloured objects to decorate their bowers; a number of insect larvae and marine worms, which incorporate objects into cases, shells and tubes, and Hermit Crabs, famed for collecting shells in which to live.

Animating the extinct

This sumptuous video features on our brand new Out of the Deep display and brings to life the two large marine reptile skeletons seen in the cases. The Museum exhibition team worked with Martin Lisec of Mighty Fossils, who specialise in palaeo reconstructions. Martin and his animators also created a longer video explaining how the long-necked plesiosaur became fossilised, as well as beautiful illustrations of life in the Jurassic seas. 
Martin explains the process of animating these long-extinct creatures:

The first step was to make 3D models of all the animals that would appear in the films or illustrations. After discussion with the Museum team, it was clear that we would need two plesiosaurs (one short-necked, known as a pliosaur, one long-necked), ammonites, belemnites and other Jurassic sea life. Now we were able to define the scale of detail, size and texture quality of the model.

In consultation with Dr. Hilary Ketchum, the palaeontologist on the project, we gathered important data, including a detailed description of the discovered skeletons, photographs, 3D scans, and a few sketches.

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We created the first version of the model to determine proportions and a body shape. After several discussions with Hilary, some improvements were made and the ‘primal model’ of the long-necked plesiosaur was ready for the final touches – adding details, mapping, and textures. We could then move on to create the other 3D models.

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The longer animation was the most time-consuming. We prepared the short storyboard, which was then partly changed during the works, but that is a common part of a creative job. For example, when it was agreed during the process that the video would contain description texts, it affected the speed and length of the whole animation – obviously, it has to be slower so that people are able to watch and read all important information properly.

A certain problem appeared when creating the short, looped animation. The first picture had to precisely follow the last one – quite a difficult goal to reach in case of underwater scenery. Hopefully no-one can spot the join!

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At this moment we had a rough animation to be finalised. We had to make colour corrections, add effects and sound – everything had to fit perfectly. After the first version, there were a few more with slight adjustments of animation, cut and text corrections. The final version of both animations was ready and then rendered in different quality and resolution for use in the display and online.

The last part of the project was creating a large illustration, 12,000 x 3,000 pixels, which would be used as a background for a large display panel. Text, diagrams and a screen showing the animations would be placed on this background, making the composition a little tricky. We agreed that the base of the illustration would be just the background. The underwater scene and creatures were placed in separate layers so that it would be easy to adjust them – move them, change their size, position etc.

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In the first phase, we had to set the colour scale to achieve the proper look of the warm and shallow sea, then we made rough sketches of the scene including seabed and positions of individual creatures. We had to make continuous adjustments as the display design developed.

Then we finished the seabed with vegetation, gryphaea shells and plankton floating in the water. The final touch was to use lighting to create an illusion of depth for the Jurassic creatures to explore.

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More Out of the Deep videos are available on the Museum website.