“Steep Cliffs!” warns a map of California’s Point Reyes National Seashore, 72 kilometers northwest of San Francisco. “The cliffs of the Point Reyes Headlands are likely to crumble and slide,” the notation continues. “Climbing on them invites catastrophe. Because of falling rocks, walking below cliffs is dangerous. Keep away!”

Dybas, C.L. 2018. Over a cliff: Northern elephant seals’ California comeback challenged by sea level rise, inbreeding. Oceanography 31(4):10–13, https://doi.org/10.5670/oceanog.2018.421.

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.