1.1 Billion Objects and Counting: Inside the Effort to Tally Natural History Specimens Around the Globe

This year, NMNH director Kirk Johnson helped spearhead an effort to add up the collections of the world’s largest museums

Collections (IZ)_credit Chip Clark, Smithsonian Institution (1).jpg
A small fraction of the more than 50 million specimens housed in the museum’s invertebrate zoology collection. Chip Clark, NMNH

2023 was a banner year for the National Museum of Natural History marked by the arrival of significant specimens, the unveiling of multiple exhibitions and hundreds of scientific publications. Tune in to the “NMNH in Review” series over the next month to learn about a new orca skeleton, historic asteroid samples and the top ten discoveries made by museum scientists this year. Read previous installments here.

With more than 148 million specimens and objects ranging from pocket-sized shrews and glimmering crystals to petrified tree trunks and giant squid, the National Museum of Natural History holds a sprawling account of how Earth has changed over the past 4.5 billion years.

According to Kirk Johnson, the museum’s Sant Director, many of these specimens help researchers forecast the planet’s uncertain future. “We're seeing rapid change in the natural world and these collections are the only place to see certain aspects of nature,” Johnson said. Because the collections contain ecological relics like extinct species, they reveal how life responded to past environmental changes and how it may fare in the future.

Johnson champions the crucial role natural history collections play in charting our planet’s future in this precarious epoch. But even a collection as large as the museum’s only reveals snippets of the planet’s ongoing story. The gaps in knowledge prevent scientists and policy makers from making the most informed decisions possible.

Kirk Johnson sits in his office at the museum in front of a display case containing specimens from the museum’s collection. Smithsonian Institution

To fill in the missing chapters of Earth’s story, Johnson teamed up with Ian Owens, the director of the Cornell Laboratory of Ornithology, and museum directors and researchers from around the world to create a global inventory of natural history specimens. “Everything that humans have ever collected to support the science of understanding the planet are in natural history museums,” Johnson said. “Collectively, all natural history museums in the world hold our physical knowledge of the planet.”

The international effort began nearly a decade ago in 2014 when Johnson met with leaders from several of the world’s largest museums. While his fellow museum directors came from a variety of academic and professional backgrounds, Johnson was pleased to hear that each of them recognized the irreplaceable value of museum collections.

The U.S. National Mosquito Collection, which is housed at the museum and curated in partnership with the Walter Reed Biosystematics Unit, contains 1.7 million specimens, the largest and most taxonomically diverse mosquito collection in the world. Paul Fetters, NMNH

Yet despite this shared understanding, the museum directors lacked a reliable way to compare the scientific holdings in each of their institutions. Efforts to digitize specimens and objects were in their infancy and many museums used different subdivisions to organize their collections. Without a shared framework, understanding what each museum had was little more than educated guesswork.

“Collectively, all natural history museums in the world hold our physical knowledge of the planet.” — Kirk Johnson, Sant Director NMNH

To get everyone on the same page, Johnson, Owens and their colleagues needed to create a simple yet comprehensive method for each museum to easily survey its entire collection. To simplify this daunting task, the team broke down the standard natural history collection into 19 different collection types spanning the entirety of biological, geological, paleontological and anthropological collections. They then mapped out 16 different marine and terrestrial geographic areas to denote where specimens were collected.

Johnson and his colleagues created a grid comparing the 19 collection types with the 16 geographic areas. Each specimen or object in a given museum’s collection would fit into only one of the graph’s 304 cells. For example, the Nation’s T. rex would only slot into the cross section of the vertebrate paleontology collection type and the North American geographic area.
The museum’s paleobiology collection has over 40 million specimens. To sort through such large collections, the researchers asked museum curators to group their collections by the geographic area where the specimens were collected. Chip Clark, NMNH

The team sent the chart to more than 150 museum directors and scientists. It could take years for scientists to calculate exact specimen counts for a single collection, let alone an entire museum. Instead, each director or scientist was instructed to fill out each cell of the chart to the nearest power of ten.

“That allowed us to make super quick estimates,” Johnson said. “We did this entire museum, which is the world's largest collection, in about two weeks.” While these figures may not be precise, most collection managers or curators have pretty accurate estimates of a given collection’s size. As a result, this rapid-fire method “gives you a sense of what you got,” Johnson said.

In a paper published this past March in Science, Johnson, Owens and 156 co-authors applied this methodology to estimate the collection sizes of 73 of the world’s largest natural history museums across 28 different countries. In total, these museums housed more than 1.1 billion specimens and objects.

An assortment of modern and fossil spiny oyster (Spondylus spinosus) shells (left) and a collection drawer full of moths from Maryland (right) from the museum’s collection. Left image: James Di Loreto and Molly Spalding, NMNH; right image: James Di Loreto, NMNH

1.1 billion specimens and objects may sound staggering. But it’s far from a total figure of what museums hold. The survey revealed that there are gaps across museum collections in remote areas including tropic, polar and marine ecosystems. Vast amounts of arthropod and microbial diversity also remain undiscovered. These gaps could provide a roadmap for coordinated collecting efforts by museums in the future.

Johnson and his colleagues are currently working on an effort to survey the collections of North America’s smaller museums. Collectively, these institutions will provide a glimpse of fossils, plants, animals and archeological artifacts from across the continent.

Johnson and Hans Sues, the museum’s curator of vertebrate paleontology, examine the fossilized skeleton of an early horse from Wyoming in the collection. Lucia RM Martino, NMNH

While there remains innumerable specimens and objects waiting to be collected and counted, the recent paper is the best effort yet to quantify a global natural history collection. Johnson thinks that understanding this collection can help unlock insights into wide-ranging issues such as climate change, food insecurity, human health, pandemic preparedness and wildlife conservation.

“We're doing it because we think that the information held in natural history museums is relevant to the future of the world in the next couple of decades,” Johnson said. “We live in a world where 4.5 billion years of evolution is now at threat. It is a critical spot to be.”

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