GrayFox LeValley 512

Gray foxes, like this young pup, take advantage of valuable habitat provided by Humboldt Bay National Wildlife Refuge.

A wide variety of mammals use Humboldt Bay National Wildlife Refuge aquatic and terrestrial habitats. Marine mammals such as harbor seal (Phoca vitulina), harbor porpoise (Phocoena phocoena) and California sea lion (Zalophus californianus) use bay habitats as well as near shore habitats. Harbor seals bear and rear their pups on exposed tidal flats, and sea lions occasionally use haulout sites near the shoreline for resting. River otters (Lontra canadensis) use the sloughs and associated riparian forest for foraging and den building.


The diversity of refuge habitats provide cover and forage for larger animals including black-tailed deer (Odocoileus hemionus) bobcat (Lynx rufus), mountain lion (Puma concolor) gray fox (Urocyon cinereoargenteus)  and porcupine (Erethizon dorsatum). Smaller mammals include the dusky-footed woodrat (Neotoma fuscipes), white-footed deer mouse (Peromyscus maniculatus), Pacific jumping mouse (Zapus trinotatus), California harvest mouse (Reithrodontomys megalotis), Trowbridge shrew (Sorex trowbridgii) vagrant shrew (Sorex vagrans), shrew mole (Neurotrichus gibbsii), California vole (Microtus californicus), and the rare white-footed vole (Arborumus albipes). Botta’s pocket gopher (Homomys bottae aticeps) is very common and important on the dunes. Bats include the big brown bat (Esptesicus fuscus bernardinus) and Yuma myotis (Myotis yumanensis saturatus). Open grassland and (seasonal) marsh habitats are preferred by black-tailed jackrabbit (Lepus californicus), brush rabbit (Sylvilagus bachmani), striped (Mephitus mephitus) and western spotted (Spilogale gracilis) skunk, long-tailed weasel (Mustela frenata), and American mink (Mustela vison), while also being utilized by some mammals mentioned above. The most adaptable mammals such as coyote (Canis latrans), gray fox, Virginia opossum (Didelphis virgiana), and raccoon (Procyon lotor) use a wide variety of Refuge habitats and food sources.