When it comes to nature, San Diego County is an exceptional place.
It has canyons and mountains, coastal cliffs and chapparal, deserts and rivers—and each of these habitats is full of life. In fact, more animal and plant species live here than any other county in the contiguous United States!
To better understand this amazing place we all call home—as well as our neighbor in nature, the Baja California Peninsula—scientists at The Nat have been growing and revisiting our natural history collection for nearly 150 years.
Like a library for biodiversity, this repository of specimens supports the work of our researchers as well as the needs of visiting scholars, government agencies, and conservation organizations alike.
Natural history collections are an especially useful research tool because each specimen contains original, tangible evidence of the time and place it came from—unlike a written recording or a photograph. A single specimen represents far more than a single data point, so we can return to each one, over and over, with new questions and new techniques—and still find new answers.
The Nat's collection—more than eight million specimens strong—spans 1.9 billion years of history, representing hundreds of thousands of species from around the world. Its strength, however, lies in its emphasis on our local region. As the oldest natural history collection in the Southwest, it is an invaluable and irreplaceable resource for understanding the past, present, and future of the Californias.
Our collections document biological diversity, provide a baseline for detecting change over time, and will answer the questions of the future. Here are just a few ways our specimens have contributed to science and society:
1960s: Our egg collection includes specimens collected both before and after the widespread use of DDT in the mid 1900s. Our former Curator of Birds and Mammals, Dr. Joseph Jehl, studied this collection and connected the decline of brown pelicans along the Baja California Peninsula to DDT accumulating and persisting in the environment. His discovery helped lead to the U.S. ban of DDT in the early 1970s.
1992: Museum paleontologists unearthed the Cerutti Mastodon, along with rocks that showed signs of human use, suggesting that people lived in the San Diego County more than 130,000 years ago. If things are as they seem, these specimens could potentially be the oldest evidence of humans in North America. Read more about this exciting, yet controversial, discovery here.
2017: Completely undetected for nearly 30 years, the San Quintin kangaroo rat was considered “likely extinct” by the IUCN, until it was rediscovered by Mammalogist Scott Tremor and Research Associate Dr. Sula Vanderplank in 2017. After this initial discovery, the team used location data from these San Quintin kangaroo rats collected in the 1920s, which helped them find more individuals in the area.
2020: Curator of Botany, Dr. Jon Rebman and researchers from the Salk Institute successfully extracted multiple chemicals with neuro-regenerative and anti-inflammatory properties from dried pressings of Yerba Santa, a common plant in San Diego County. These chemicals could be an effective therapy for people with dementia or Alzheimer’s disease.
Ongoing: Environmental biologists require permits to monitor the endangered Quino checkerspot butterfly. To obtain these permits, they must pass a species identification test because the Quino checkerspot closely resembles other, non-threatened subspecies within the same genus. Researchers working for the State of California, as well as environmental consulting companies, frequently visit our collection to brush up on their butterfly identification skills.
Perhaps the best part of keeping a natural history collection is watching new scientific questions arise, and answering them in ways our predecessors never thought possible. In the early 1900s, our scientists could never have guessed their collections would later be sampled for DNA, X-ray imaged, or used to study climate change. How will the specimens we are adding to our collection today be of use a hundred years from now? Only time will tell.
Only a fraction of The Nat's 8+ million specimens are on display, but our behind-the-scenes vaults have some great stories to tell. Here are a few fun facts from our shelves: