Some people visit to read about the types of wood Victorian manufacturers used to make walking sticks. Others want to see a picture of a Tasmanian tiger or admire the field diary of one of the first botanists known to explore Antarctica.
Over the past 20 years, more than 64 million pages have been made freely available through the Biodiversity Heritage Library (BHL) – a digital treasure trove for nature lovers. More than 680 museums, universities, libraries, and scientific institutions from China, Singapore, Australia, New Zealand, Europe, Africa, Mexico, Canada, and the US have contributed to the library.
This week, a report from the Royal Botanic Gardens (RBG) at Kew highlighted how digitisation is playing a key role in “transforming our ability to understand and respond to the climate and biodiversity crises.” But it was the creation of the BHL 20 years ago that first showed how bringing centuries of scientific knowledge online can lead to transformative discoveries and insights about the natural world.
David Iggulden, who chairs the BHL executive committee alongside his role as head of data and digital, library and archives at RBG Kew, describes the library as an invaluable and “absolutely essential” resource for scientists in the field. But it is also used by scientific researchers, environmental historians, educators, art historians, artists, citizen scientists, and members of the public who – like Iggulden – simply enjoy browsing its contents on a rainy weekend.
“I sometimes get lost in it, looking at the various collections,” he says. “I think it’s amazing that we can explore such a wide range of different collections from very different institutions.”
Along with published biodiversity literature and journals, there are letters, illustrations, climate records, field diaries, ecosystem profiles, distribution records, and manuscripts that tell the original stories of how a particular species was collected or detail voyages of discovery.
The oldest book is one of the earliest Western medical manuscripts, a medieval pharmacopeia called the Circa instans, which dates back to around 1190. It is considered a key text in the development of modern botany and helped bring clarity across medieval Europe by standardising plant names and their uses. It was digitised by the New York Botanical Garden last year.
Another highlight for Iggulden is an 1892 illustrated exhibition catalogue by Henry Howell & Co, a Victorian company based in London that marketed itself as the world’s largest manufacturer of walking sticks.
Catalogues like this are useful for scientists studying plants used for economic purposes, as well as the importance and characteristics of wood and how it has been used throughout history, he says. “It’s a really fascinating find – and quite different from what you’d expect in the BHL.”
One of the most significant books in the collection is the botanist Sir Joseph Hooker’s illustrated Antarctic journal, which includes his watercolour sketches of two volcanoes first sighted in 1841 during his expedition to the continent with Captain James Clark Ross. “It’s the personal account of Hooker’s adventure … to the Antarctic and the sights he saw there,” says Iggulden.
Being able to share such unique, handwritten manuscripts with the world fulfils one of the main goals of the BHL, says Nicole Kearney, who leads the AustraliA branch of the library is based at Museums Victoria. “I once uploaded a handwritten field diary about birds in Australia, and someone who was studying river flooding in the region wrote to me and said: ‘You’ve just given me this incredible resource. I can now tell every time this river flooded between 1947 and 1957’—because it was all recorded in that diary from the mid-20th century, which I thought was only about birds.”
It is considered the earliest known color publication on fish, yet about 10% of the species are completely imaginary.
Nicole Kearney
During the pandemic, historical journals uploaded to the BHL helped scientists show that there had been a “massive change” in the distribution and abundance of rare Australian orchids during the “black summer” wildfires in late 2019 and early 2020. “That meant those orchid species could be reassessed, and their threatened species status was changed as a result,” Kearney says.
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Handwritten pages from the 1947–1957 Australian ornithological field diaries of A. Graham Brown. Photographs: Museums Victoria/Biodiversity Heritage Library
When she talks about the role the BHL plays for scientists, she often quotes Charles Darwin: “The cultivation of natural science cannot be efficiently carried on without reference to an extensive library.”
She says: “I’m sure Darwin would agree that, in today’s world, it is essential that we can access the world’s biodiversity knowledge online. And that this knowledge is freely available to everyone.”
One of her favorite books in the collection is The Mammals of Australia by British naturalist John Gould, published in 1863. It features a striking illustration of a Tasmanian tiger, a native Australian marsupial that was hunted to extinction after it was—perhaps wrongly—blamed for killing sheep. “The last one died in a zoo in Tasmania in 1936,” says Kearney. “It was such a stunning creature. It had a pouch but looked very much like a dog or wolf with stripes. There is nothing else like it in Australia, and nothing like it exists today.”
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The entry for the thylacine, or Tasmanian tiger, in The Mammals of Australia (1863) by British naturalist John Gould. Photographs: Smithsonian Libraries and Archives/Biodiversity Heritage Library
The BHL Flickr album is followed by tens of thousands of people and highlights some of the more unusual copyright-free illustrations in its collection (some of which have been turned into an award-winning jigsaw puzzle app, The Art of Fauna).
One popular album is Louis Renard’s 18th-century book, Poissons, Ecrivisses et Crabes, which was uploaded to the BHL in 2016. It features an illustration of a mermaid and other imaginary creatures mixed in with scientifically accurate representations of real fish, crayfish, and crabs.
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The mermaid and another imaginary creature illustrated in Poissons, Ecrevisses et Crabes by Louis Renard, 1754. Photograph: Ernst Mayr Library/Museum of Comparative Zoology/Harvard University/Biodiversity Heritage Library
“It was originally published in 1719 and is considered the very earliest known color publication on fish, yet about 10% of the species are completely imaginary,” says Kearney. “It’s a really important part of scientific literature from the Age of Enlightenment, [when] people were exploring parts of the world that had never been seen before. Artists would interpret what they were told and copy drawings from other artists who may never have seen the species themselves,” says Kearney. “They believed they were all real.”
The BHL was born 20 years ago after librarians came up with a radical idea to improve global research into climate change and biodiversity loss at a transformative moment in internet history. It was the dawn of Web 2.0, when using the internetThe internet for networking and socializing was just starting to become popular, and there was a growing sense of optimism and opportunity. What if ten major museums and institutions in the UK and the US digitized their historic biodiversity literature collections to create a single online library that every scientist around the world could access for free?
At the time, the idea of working internationally on a large-scale digitization project was “really revolutionary,” says Iggulden.
[Image: An excerpt and illustration from Sir Joseph Hooker’s illustrated Antarctic journal 1839-43. Photograph: Trustees of the Royal Botanic Gardens, Kew/Biodiversity Heritage Library]
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Today, however, the future of the world’s largest open-access digital library for biodiversity literature is at risk. Earlier this year, the Smithsonian Institution—which has faced severe funding cuts under the Trump administration—stopped hosting the BHL’s administrative functions, paying some staff salaries, and supporting its technical infrastructure. “A ‘tick over budget,’ just to keep it running as it is, would ideally be about a million dollars a year—and we only have funding, we estimate, until the end of 2027,” says Iggulden.
“It would be just horrendous—devastating, really—to lose it after coming so far and unlocking so much.”
Even additions to the library’s Flickr page have been paused because “we don’t have the resources to keep adding to it,” says Kearney. “There is so much more functionality we could bring in [to the BHL] if we had the money to incorporate AI, improved optical character recognition software, and a mobile-friendly and multilingual platform,” she says.
[Image: Illustrations from Poissons, Ecrevisses et Crabes by Louis Renard, 1754. Photograph: Ernst Mayr Library/Museum of Comparative Zoology/ Harvard University/Biodiversity Heritage Library]
Iggulden says the potential for BHL to use AI to unlock data is huge. “AI is a real positive for BHL,” he says. “The library contains vast amounts of taxonomic, geographical, ecological, and specimen-level knowledge that remains inaccessible to modern computational workflows. So, unlocking this at scale would create new opportunities for biodiversity synthesis, collections linkage, historical ecological analysis, and AI-assisted scientific discovery.”
Kearney says the journey of enlightenment told by the books in the BHL can remind us of how much we still don’t know about the natural world, and help us rediscover a sense of wonder and awe about the species that have—and have not—gone extinct.
“The BHL is fundamental to our understanding of all the species we share this world with, and our ability to save them,” says Kearney. “We now have 64 million pages of knowledge at our fingertips, which we need to make more discoverable and accessible. There’s so much more we could be doing.”
[Image: John Gould’s illustration of the thylacine, also known as the Tasmanian tiger or Tasmanian wolf, in his 1863 book, The Mammals of Australia. Photograph: Smithsonian Libraries and Archives/Biodiversity Heritage Library]
Readers can help secure the future of the Biodiversity Heritage Library and keep its collections free and open to the world by clicking the Donate button at biodiversitylibrary.org.
Frequently Asked Questions
Here is a list of FAQs about the digital library offering 64 million pages of scientific knowledge written in a natural tone with clear simple answers
BeginnerLevel Questions
Q What exactly is this digital library everyone is talking about
A Its a huge online collection of scientific papers books and research datatotaling 64 million pagesthat anyone can access for free Think of it as a public library for science but you dont need a card
Q Is it really completely free No hidden fees or subscriptions
A Yes completely free No signup no credit card no subscription The whole point is to make scientific knowledge available to everyone
Q Im not a scientist Would I even understand anything in there
A Absolutely While many documents are technical theres plenty for curious nature lovers field guides historical expedition reports species descriptions and illustrated botany books You can search for simple topics like butterflies of North America or how trees grow
Q How do I search for something say mushrooms in the Pacific Northwest
A Just type those words into the search bar The library will show you any related books articles or images from its 64 million pages
Q Can I download the books or articles to read offline
A Yes most items can be downloaded as PDFs or other common file formats You can save them to your phone tablet or computer for reading anywhere
Advanced Practical Questions
Q What organizations contributed to this 64millionpage collection
A Its a collaboration of major natural history museums botanical gardens and research libraries worldwide Key partners include the Smithsonian the New York Botanical Garden and the Missouri Botanical Garden
Q How is this different from Google Scholar or Wikipedia
A Google Scholar finds citations and links to articles Wikipedia summarizes knowledge This library gives you the actual full text of rare outofprint and historical scientific works you cant find anywhere else for free
Q I found a 150yearold book about birds Is the information still accurate
