| Humboldt's flying squirrel | |
|---|---|
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Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Sciuridae |
| Genus: | Glaucomys |
| Species: | G. oregonensis |
| Binomial name | |
| Glaucomys oregonensis (Bachman, 1839) | |
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Humboldt's flying squirrel (Glaucomys oregonensis) is one of three species of the genusGlaucomys, the onlyflying squirrels found inNorth America. The squirrel was named after the naturalistAlexander von Humboldt and California'sHumboldt County, which is one of the areas inhabited by the squirrel.[2]
Using genetic analyses, Arbogast et al. (2017)[2] showed that Humboldt's flying squirrel, previously thought to be conspecific with thenorthern flying squirrel, was actually a distinct species. TheSan Bernardino flying squirrel subspecies (G. o. californicus) is considered aCritically Imperiled Subspecies byNatureServe.[3]
They do not actually fly but glide from tree to tree.[4] They are similar in appearance to the northern flying squirrel, however, they are generally smaller and have darker pelage. They are good gliders but clumsy walkers on the ground.
Under ultraviolet light, females and males of all 3 species ofGlaucomys fluoresce in varying intensities of pink on both dorsal and ventral surfaces.[5] The fluorescence is hypothesized to help the flying squirrels find each other in low light and mimic the plumage of owls to evade predation.[6]This hypothesis has been challenged by Toussaint et al. (2022)[7] who instead suggest that the pink luminescence is a byproduct of the body's waste management. Moreover, these authors argue that it is far from evident that UV illuminating sources that occur naturally are sufficient to elicit luminescence distinguishable from ambient visible light. An ecological role for the pink luminescence is therefore not likely.
They feed on a variety of plant material as well as tree sap, fungi, insects, carrion, bird eggs and nestlings. They mostly breed once a year in a cavity lined with lichen or other soft material. Unlike most members of their family, flying squirrels are strictly nocturnal.[8] They nest in the tops of the trees away from the ground and predators.
Humboldt's flying squirrels are found in coniferous and mixed coniferous forests from southernBritish Columbia to southernCalifornia.[9] They live in thick coastal forests where there is plenty of room for them to glide from tree to tree. Populations of Humboldt's flying squirrels are more concentrated in old forests where the relatively stable environment allows for fewer offspring in each litter.[10]
