The following sources were consulted in the preparation of the article “13 places in America where animals outnumber people.”
- 2022 northern fur seal pup production and adult male counts on the Pribilof Islands, Alaska.
- Brown Bear Management Report and Plan, Game Management Unit 4
- The Battle for Bracken Cave
- Muskox management controversies in North America
- Horses of Assateague Island Population and Habitat Viability Assessment Workshop Report
- Scientific Studies on Dry Tortugas National Park: An Annotated Bibliography
- Rates of increase in gray seal (Halichoerus grypus atlantica) pupping at recolonized sites in the United States, 1988–2019
- Seabirds (circular C1198)
- Decline and Recovery of the Island Fox: A Case Study for Population Recovery
- Unexpected medical issue grounds Isle Royale wolf-moose survey
- Walrus Islands State Game Sanctuary Annual Management Report 2021
