Edited by Charlotte Kirchner, some rights reserved (CC BY-SA)
Photo Credits
- 1. (c) pfaucher, some rights reserved (CC BY-NC), uploaded by pfaucher
- 2. (c) Bering Land Bridge National Preserve, some rights reserved (CC BY)
- 3. (c) Yersinia pestis, some rights reserved (CC BY-NC-SA)
- 4. (c) Peter Trimming, some rights reserved (CC BY)
