UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory
California Native Red Foxes

(Last updated 1/6/09)red fox

This research in being conducted in the context of a broader collaborative effort among Ben Sacks, Keith Aubry, Sam Wisely, Mark Statham, John Perrine, and others aimed at elucidating the worldwide phylogeography of the species.  The red fox as a species is a habitat generalist. Red foxes also have the widest geographic distribution of any non-human (non-domesticated) mammal. However, some populations, including one native to California, have become isolated over time and are thought to have evolved narrow, specialized habitat affinities. The Sierra Nevada red fox is critically endangered and represents one of four relict populations in southwestern North America (including those in the northern Cascades and Rocky Mountains) tracing their roots to the mid-Pleistocene. It is thought that this and two other southwestern relictual populations are restricted to, and possibly adapted to, subalpine habitat. Current work on the Sierra Nevada red fox in collaboration with John Perrine and Pete Figura (California Dept. Fish and Game) aims to estimate the population abundance using fecal samples collected in the Lassen Peak region through a combination of species ID using mtDNA markers and identification of individuals via genotyping of scats at 34 microsatellite loci.

We became especially interested in the origins of a second population in California, that in the Sacramento Valley, which after a molecular genetic comparison involving historic museum specimens appeared to be native (Perrine et al. 2007). This population, which dates at least as far back as the late 1800s, predates fox farming but nevertheless has been presumed nonnative due primarily to its occurrence in habitat wholly uncharacteristic of the other relictual populations. At odds with conventional wisdom, which has it that these foxes were brought in for hunting purposes from the east via railroad, our genetic data indicate that this population shares much more recent ancestry with that of the native Sierra Nevada population than with eastern fox populations or known nonnative populations in California (largely of Alaskan/Canadian/eastern US ancestry).  Most recently, we have uncovered additional haplotypes in the Sacramento Valley derived from a single widespread endemic haplotype, making it a virtually certainty that this population is native.  A basic question in this research is on the relative contributions of specialized adaptation versus historical contingency in explaining the distribution of this anomolous red fox population.

In collaboration with Dr. Heiko Wittmer of WFCB in UC Davis and the California Department of Fish and Game, we have recently expanded our research on the native Sacramento Valley red fox to include a combined field-genetic study aimed at assessing the current status of and threats to this population.  This work is community-based, involving volunteers and a web-based reporting system to gain information from the public.  Although in its infancy, our first two field seasons were highly successful, resulting, for example, in the location of 23 reproductive dens, from which data were collected on litter size and prey use.  Noninvasively sampled genetic material was also obtained, extracted, and successfully sequenced and genotyped at mtDNA and microsatellite loci from >100 individuals. 

Led byMarcelle Moore, as part of her MS Thesis work, we have put together a panel of 34 red-fox specific microsatellite markers (primers designed from a worldwide sample of red fox sequences) and a sex marker designed to amplify fecal DNA. These markers are currently being used to assess familial relationships among scats collected at dens along with road-killed red foxes to better understand dispersal movements in the Sacramento Valley and are being used to assess the degree (if any) and direction of hybridization between parapatric native Sacramento Valley red foxes and nonnative red foxes in the San Joaquin Valley.

Mark Statham and Mike Hansen are working on camera survey methodologies that can be used to detect the presence of red foxes and other carnivores. Gina Tarbill will conduct her MS research using remote-triggered camera surveys, based partly on this methodology, to compare habitat use between native and nonnative red foxes.

Mourad Gabriel is examining the distribution, prevalence, and phylogenetic affinities of parvoviruses found in red fox scats from native and nonnative dens.

red foxes
Museum specimens are critical to this research; these are from the
National Museum of Natural History (photo courtesy of Sam Wisely)

Collaborators and sample donors:
California Department of Fish and Game, Heiko Wittmer (UC Davis), John Perrine (Cal Poly San Luis Obispo), Keith Aubry (USFS), Sam Wisely (KSU), Mark Statham (KSU), John Pollinger (UCLA), Bob Wayne (UCLA), Dairen Simpson (freelance predator specialist), Bob Jones (UC Berkeley, Museum Vertebrate Zoology), Brian Cypher (CSU Stanislaus, USFWS/Endangered Species Recovery Program), Melissa Gilbert (Marine Wildlife Veterinary Care and Research Center), Jerry Wiscomb (USDA/Wildlife Services), Craig Coolahan (USDA/Wildlife Services), Bob Beach (USDA/Wildlife Services), Mike Bodenchuck (USDA/Wildlife Services), Mark Jensen (USDA/Wildlife Services), Mark Collinge (USDA/Wildlife Services), Don Kemner (Idaho Dept. Fish and Game), Hance Clayton (Idaho Trappers Association); many, many Wildlife Services specialists

International collaborators and sample donors: Love Dalen (Stockholm Univ, Sweden), Peter Savolainen Royal Inst Tech., Sweden), Arman Ardalan (Natl. Inst. Gen. Eng. Bioteck, Iran), Natalia Illarionova (Orel State institute of arts and culture, Russia)

Collaborating museums and collections: Museum of Vertebrate Zoology (UC Berkeley), NAtional Museum of Natural History (Smithsonian Institution), Dennis G. Raveling Museum (UC Davis), Royal Ontario Museum, California State University, Chico; Burke Museum (Univ. Washington), Natural History Museum of Los Angeles County, Santa Barbara Natural History Museum

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL