News Release

SNAPSHOT USA: First-ever nationwide mammal survey published

Peer-Reviewed Publication

North Carolina Museum of Natural Sciences


image: Pronghorn (Antilocapra americana) enjoys the sun in the snowy hills of southern Wyoming, view more 

Credit: Jesse Alston, University of Wyoming

[RALEIGH, N.C.] - How are the squirrels doing this year? The bears? The armadillos? How would you know? A new paper published June 8 sets up the framework for answering these questions across the United States by releasing the data from the first national mammal survey made up of 1,509 motion-activated camera traps from 110 sites located across all 50 states.

Unlike birds, which have multiple large-scale monitoring programs, there has been no standard way to monitor mammal populations at a national scale. To address this challenge, scientists from the North Carolina Museum of Natural Sciences and the Smithsonian Conservation Biology Institute recently collaborated with more than 150 scientists on the first-ever nationwide wildlife survey, called Snapshot USA. "Our goal was to provide a space for researchers from all 50 states to contribute a subset of their data to a broader initiative to maximize our coverage of the country and better understand drivers of mammal distributions to best inform conservation as rapidly as possible," said the Museum's Curator of Mammalogy Michael Cove, lead author of the new paper.

For two months in fall 2019 researchers collected more than 166,000 images of 83 different mammal species. White-tailed deer were the most common species detected (34,000+ times at 1,033 sites), followed by eastern gray squirrels and raccoons. Pygmy rabbits, mountain beavers, hog-nosed skunks and marsh rabbits were among the least common mammals photographed. Yet, the overall detection winner was the coyote, which was detected in all 49 continental states -- they have not made it to Hawaii yet. All the data are archived at the Smithsonian Institution's eMammal database and published as part of the new paper.

In an interesting twist, developed areas tended to have the highest overall mammal detections, with three of the top five sites for total mammal activity being urban -- Urbana, IL.; Baltimore, MD.; and Washington, D.C. "These new data show that the urban mammal paradox, with more animals actually living close to people, is not just an isolated phenomenon," said coauthor Roland Kays, a scientist at the museum and at NC State University.

When comparing particular species across the country, North Carolina stood out for being in the "Top 10" for the relative abundance of black bears (#3 Dare County, #4 Craven County, #7 Pender County, #8 Haywood County); bobcats (#5 Dare County); coyotes (#8 Haywood County); white-tailed deer (#5 Surrey County, #9 Alamance County, #10 Moore County); and turkeys (#8 Craven County, #9 Burke County and #10 Moore County). Nationally, ranking of top sites for select mammal species can be found at

The research results appeared June 8 in Ecology, a publication of the Ecological Society of America, the nation's largest organization of professional ecologists. The publication makes the 2019 survey data available online for anyone to use for research questions, such as the evaluation of changes in animal populations over time or informing conservation strategies for threatened and endangered species. "This project involved a remarkable level of cooperation and data sharing that will have to be the standard going forward to adequately monitor our valuable wildlife resources at the national scale," adds William McShea of the Smithsonian Conservation Biology Institute.

The scientists repeated the survey in fall 2020 likely providing insights on the effects of the COVID-19 pandemic on wildlife distributions and habitat use -- resulting data will be available as the eMammal database is updated in 2021.


Note to Editors: The study abstract follows.

"SNAPSHOT USA 2019: The first coordinated national camera trap survey of the United States"

Published: June 8, 2021, Ecology


Abstract: With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the Snapshot USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August - 24 November of 2019). We sampled wildlife at 1530 camera trap sites from 109 survey arrays covering 12 different ecoregions across four development zones. This effort resulted in 165,426 unique detections of 80 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results of this survey are the first standardized camera trap survey of the USA, and possibly the largest coordinated mammal assessment of its kind. All of the 2019 survey data are made available herein. We will repeat surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic filters, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans.


Michael V. Cove1,2, Roland Kays2,3, Helen Bontrager1, Claire Bresnan1, Monica Lasky3, Taylor Frerichs1, Renee Klann1, plus ~150 others.

1Smithsonian Conservation Biology Institute, Front Royal, VA 22630
2North Carolina Museum of Natural Sciences, Raleigh, NC 27601
3Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27607


This project was a huge collaboration effort. Thanks to data contributors, students, interns, and citizen scientists with data collection and camera trap image review. The Smithsonian Institution provided support and data storage in the Smithsonian repository.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.