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15 things you didn't know about the Naturalis collection

Posted on 04-07-2017 by Eulàlia Gassó Miracle

Coverphoto: Curator Eulàlia Gassó Miracle in the Naturalis collection

You certainly already knew that Naturalis houses one of the worlds biggest collections of natural history. But did you also know that with the last count, we came to more than 42 million (!) objects? There are many more fun facts to tell about our collection. Curator Eulàlia Gassó Miracle wrote 15 of them down!

1. The Naturalis collection is actually yours

Naturalis Biodiversity Center holds, preserves and curates the largest Dutch natural history collection, but it does not own it. The collection is part of our Dutch heritage, property of the state and of all Dutch people. It is for preservation’s sake that only a fraction of the collection is open for the general public.


2.  You can admire the collection online

Although the objects are protected and kept in a climate controlled, unaccessible tower, Naturalis has made a gigantic effort to free up the information and to exhibit its collections virtually. It can be accessed through several portals, like the BioPortal, Wikipedia or, for the scientific data, GBIF (Global Biodiversity Information Facility). The collection of extinct birds is even available in 3D!

The digitization process is an ongoing project in Naturalis, so more and more specimens will be accessible online. Curious? Find out more here.

Cuban Macaw. Source: Bioportal. Click here for a 3D view of the specimen.

3. The collection got a building specially designed for it in 1915

At the end of the 19th century it became clear that the old building for the museum collection in the Papengracht in Leiden was too small, too damp and too inconvenient. After years of fierce discussions between the director, F.A. Jentink, and the government, the construction of Jentink’s ideal museum started in 1905. The collection moved to the new building at the Raamsteeg in Leiden in 1915.

As there was no electricity available yet, the building was especially designed to maximize daylight. Big windows and an open grid floor allowed daylight to reach almost every corner. No gas or oil lamps were allowed because the risk of a fire was too big. The staff had to go home early during the winter. Electric lighting was installed in 1919 in the entrance hall and the library; the collection did not see an electric light bulb until 1929.

There were special wings for the alcohol and dry collections, researchers offices and rooms for the technical staff. The wing for public exhibitions never came, as the museum run out of funding and that wing had been scheduled to be built as last.

Photos: left: 1913-1990: Raamsteeg in Leiden. Source: Wikipedia. Right: Raamsteeg building floors, designed to maximize daylight.


4. We had an electronic microscope in the loo

In the 1960s, the museum had enough funds for an electron microscope, to the scientists delight. However, the microscope was terribly heavy and the building floors at the Raamsteeg were not strong enough to support its weight. It had to be installed somewhere on the ground floor. The only available space that could both support the weight of the thing and supply the necessary space was the toilet. And so it came that the loo was transformed into a very modern, highly specialized microscopy laboratory.

 5. The museum provided shelter during WWII

The Apollo butterfly collection of the jewish businessman Curt Eisner was already renowned in the 1940’s. When Hitler rose to power, Eisner fled his home town in Silesia and took with him his collection, the biggest in the world. After Eisner had found shelter in The Hague, he asked the museum to shelter his collection as well. The director, H. Boschma, agreed.

When The Netherlands fell under Nazi rule, German officials demanded the delivery Eisner collection to them as German heritage. Boschma replied matter-of-factly that the Eisner collection had been officially given to the museum and was therefore propriety of the Dutch government, although that had never happened. Boschma asked the officials to return a week later, as he he seemed to have “misplaced” the papers. When they returned, Boschma presented them some papers, hastily produced that week, and they left empty handed.

Years later an American museum offered Curt Eisner a large sum of money to buy his collection. Eisner, in gratitude to Boschma, declined the offer and donated the collection to the Leiden museum instead - now officially.

Eisner remained in The Netherlands and kept working in his collection until he died at age 91.

Photos: left: Curt Eisner in 1974. Source: Wikipedia. Right: A small part of the Eisner collection in Naturalis. Photo: Eulàlia Gassó.

6. We treasure the bad teeth of a famous anthropologist

Inspired by Darwin, Eugène Dubois became a paleoanthropologist, dedicated to find and study man’s evolutionary history. He was determined to find the “missing link” between apes and humans, an ape-like human fossil that would prove for once and for all that man descended from primates. After many adventures, he finally succeeded in 1891. He found the remains of Pithecanthropus erectus (later redesignated Homo erectus), or "Java Man". The fossil aroused heated discussions that embittered Dubois and made most of his life miserable.

In order to study the relations between his fossils, apes and man, Dubois needed not only fossils, but also ape and human skulls, including their teeth. Dentition is a key feature for recognizing species, so when any of his bad teeth was extracted by the dentist, he kept it in a box for further study. His mammal fossil collection, together with his archive, models, and teeth, are now part of the Naturalis collection.

Photos: left Eugène Dubois. Source: Wikipedia. Right: Dubois' own molar.

7. The collection’s worst enemy is a beetle

Museum beetles are our worst nightmare. Their larvae diet consist of dried skin, hair and dried insects. When they enter a museum collection, the damage to the specimens is irreversible. The larvae will eat their way into stuffed mammals and birds, insects and even the labels attached to them. But these are not the only critters we fear. Museum beetles belong to the family of Dermestidae, which include carpet beetles and larder beetles, all with a taste for natural history specimens. Some types of moths, wood-eating beetles, silverfish and termites are also in our black list. The solution: IPM, or Integrated Pest Management.

IPM measures includes temperature and humidity control, regular disinfection by fumigation, isolation and quarantine of new or infected specimens and trapping, plus constant monitoring. The Naturalis collection tower is kept constantly at 18 degrees Celsius, with an humidity of 50%. It is regularly disinfected and the collection managers always keep a watchful eye on their specimens, just in case.

Photos: left: fluffy but terrifying, the larva of a museum beetle, Dermestes verbasci. Right: adult museum beetle. Source: Wikipedia.

8. We keep some of the objects in top-secret places

For safety reasons, some of our most precious collection items are not only kept under lock and key, but their precise location is top-secret. This concerns extinct and rare animals, like the thylacine, and the precious stones, pearls and ivory objects. Data related to these objects is also kept secret: the exact floor or cabinet where they are stored is never revealed. Other objects we hide from thieves are the rhinoceros horns, a wide range of illegal souvenirs, like coral jewels and fur coats, all plants with addictive properties - that is, drugs -  and psychedelic mushrooms.


Photo: Pearls from the Naturalis collection.

9.  The collection is still growing

The collection is an archive for biodiversity and an important tool for research. Without the collection, nature has no past, and we cannot understand nor predict its future. In order to aid research - now and for future generations -, new objects are added to the collection. This includes new collection items, but also older collections that the museum “inherits”.

When our researches go on expedition, samples need to be taken for reference and further study. These samples become part of the collection when their work is completed. Also, amateurs and independent researchers more often than not choose to donate their private collections to the museum. However, we never, ever, buy any natural history objects! It would only stimulate commerce in wildlife, a threat to the biodiversity we are bound to protect.

Photo: Naturalis Amazon expedition, 2013. In this blog you can read more about the Naturalis expeditions.

10. You can see Lake Victoria on the collection tower

When the museum tower was being built between 1997 and 1998, the Dutch artist Giny Vos made a special piece of art for it. High on the tower wall, dots of light move, collide and change continuously within the black shape of Lake Victoria. It represents life and its evolution. Her work was inspired by the microorganisms living in a drop of water, and it is called Lust for Life.  

Photo: Lust for Life on the collection tower of Naturalis. Source: Giny Vos.

11. Naturalis Biodiversity Center is only 6 years old.

In 2010, some Dutch university natural history collections were facing their demise because of financial problems. After arduous negotiations, the National Herbarium (until then, under the care of the Leiden University, including their branch in Wageningen), the Zoölogisch Museum Amsterdam (from the University of Amsterdam) and the Nationaal Natuurhistorisch Museum Naturalis (already in Leiden) merged to form the new Naturalis Biodiversity Center in 2011.

Each of these collections has a rich history and all are of great scientific importance. Together, they account for 42 millions plants, animals and geological objects. Our oldest objects date back to the 16th century, like the Italian “En Tibi” Herbarium, or the 18th century “blauwbok”, or blue antelope (Hippotragus leucophaeus) that lived in South Africa until it went extinct around 1800. The collection is rich in objects from The Netherlands and the European continent, but also from South East Asia, Tropical America and West Africa.

Photo: One of the oldest herbariums in the world: En Tibi Perpetuis Ridentum Floribus Hortum (1545).

12. We have a Rare Book Room.

Along with the huge collection of 42 million animals, plants, stones and fossils, Naturalis also keeps a vast scientific archive and a huge library. The archive is the ‘memory’ of the collection. It contains manuscripts, photographs, letters, field books, diaries, drawings and even paintings. It is kept in the Rare Book Room, where we also keep old, unique and extraordinary books. The room, situated in the collection tower, it is closed for the general public and researchers can access it only with our archivist permission. The Rare Book Room is, like the rest of the tower, climate controlled and monitored for pests at all times. You can read more about it here.

Photos: left: The Rare Book Room from Naturalis. Right: Manuscripts by C.J. Temminck, founder and first director of Naturalis. Photos: Eulàlia Gassó.

13. You can explore Naturalis on Google.

The museum exhibitions closed in August 2016 for renovations and a much needed expansion. With the exception of small exhibitions in the Pesthuis building like “T-rex in Town”, Naturalis will remain closed until 2019. You can still visit one virtually of the most beautiful exhibitions rooms, the Nature Theater, and read about many highlight objects at Google Arts & Culture.

Photo: The design for the new Naturalis, to be completed in 2019. Photo: Neutelings Riedijk Architecten.

14. We marinate bodies in hot steel tanks.

When fresh - but dead - animals arrive at Naturalis, they are prepared by our expert taxidermists. The process involves skinning and cleaning the bones. Sometimes, the animals are too big to be prepared just by scraping the flesh from the bones. Big animals, like stranded whales, are dismembered first and then put into special steel tanks with hot water. The idea is quite simple: we let the flesh rot in a controlled environment, until the the bones are clean. The technique is called “maceration”. Using only hot water, we let bacteria do the dirty job. There is no need of chemicals that might damage the bone structure or its DNA. Downside: it smells. Badly.

15. We also collect used toothbrushes and cat’s whiskers

Naturalis is a high-tech institute. There are advanced microscopes, a state-of-the-art DNA lab, 3D imaging systems and much more. But did you know that we also value more simple tools? In our toolkits you might find old toothbrushes and cat’s whiskers. It might sound gross, but a toothbrush is extremely useful to clean and restore bones. Another example of a low-tech but incredible convenient utensil: a cat’s whisker, to splint broken butterfly wings. It is an organic material, flexible yet strong, easy to handle and in large supply in The Netherlands: we are a cat-lover nation.

Photos: left: cleaning a whale specimen with a toothbrush. Right: a white cat whisker as a splint for a broken butterfly wing.

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