The
gray fox is a
mammalMammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
of the order
CarnivoraThe diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...
ranging throughout most of the southern half of
North AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
from southern
CanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
to the northern part of
South AmericaSouth America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
(
VenezuelaVenezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
and
ColombiaColombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
). This species and the closely related Channel Island fox (
Urocyon littoralis) are the only living members of the
genusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
UrocyonThe genus Urocyon is a genus that contains two living Western Hemisphere foxes in the family Canidae, the Gray Fox and the closely related Island Fox which is a dwarf cousin of the Gray Fox; as well as one fossil species, Urocyon progressus.Urocyon and the...
, which is considered to be among the most primitive of the living canids. Though it was once the most common fox in the east, and still is found there, human advancement allowed the red fox to become more dominant. The
Pacific StatesThe Pacific States form one of the nine geographic divisions within the United States that are officially recognized by that country's census bureau. There are five states in this division — Alaska, California, Hawaii, Oregon, Washington — and, as its name suggests, they all have...
still have the gray fox as a dominant.
Origin
The gray fox appeared during the mid
PlioceneThe Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
epoch ago (
AEOAppearance Event Ordination or AEO is a scientific method for biochronology through the ordering of the appearance of fossil mammal genera by multivariate analysis, using conjunctional and disconjunctional range distributions in large sets of data.-Process:AEO is based on faunal overlap and...
) with the first fossil evidence found at the lower 111 Ranch site,
Graham County, Arizona-2010:Whereas according to the 2010 U.S. Census Bureau:*72.1% White*1.8% Black*14.4% Native American*0.5% Asian*0.1% Native Hawaiian or Pacific Islander*2.8% Two or more races*8.3% Other races*30.4% Hispanic or Latino -2000:...
with contemporary mammals
giant slothMegalonyx is an extinct genus of giant ground sloths of the family Megalonychidae endemic to North America from the Hemphillian of the Late Miocene through to the Rancholabrean of the Pleistocene, living from ~10.3 Mya—11,000 years ago, existing for approximately .-Taxonomy:The generic name...
, the elephant-like
CuvieroniusCuvieronius is an extinct New World genus of gomphothere. It is named after the French naturalist Georges Cuvier, stood 2.7 m tall and looked like a modern elephant except for its spiral-shaped tusks.-Origin:...
,
Large-headed llamaHemiauchenia is a genus of lamine camelids that evolved in North America in the Miocene period approximately 10 million years ago. This genus diversified and moved to South America in the early Pleistocene as part of the Great American Interchange, giving rise to modern lamines...
, and the early small horses of
NannippusNannippus is an extinct genus of horse endemic to North America during the Miocene through Pliocene, ~13.3—3.3 Ma, living approximately .Nannippus lived as far south as Central Mexico to as far north as Canada , to California in the west, North Carolina and Florida Nannippus is an extinct genus...
and
EquusEquus may refer to:* Equus , a genus of animals including horses, donkeys, zebras and onagers* Equus , a play by Peter Shaffer* Equus , a film adaptation of the Peter Shaffer play...
. Genetic analyses of the fox-like canids confirmed that the gray fox is a distinct genus from the red foxes (
Vulpes ssp.). Genetically, the gray fox often clusters with two other ancient lineages, the east Asian
Raccoon dogThe raccoon dog , also known as the magnut or tanuki, is a canid indigenous to east Asia. It is the only extant species in the genus Nyctereutes...
(
Nyctereutes procyonoides) and the African
Bat-eared foxThe bat-eared fox is a canid of the African savanna, named for its large ears. Fossil records show this canid to first appear during the middle Pleistocene, about 800,000 years ago....
(
Otocyon megalotis). Chromosome number is 2n=66. Recent genetic analysis has shown that the gray fox migrated into the northeastern United States post-Pleistocene in association with the Medieval Climate Anomaly warming trend. The Channel Island fox is likely descended from mainland gray foxes.
Description and behavior
The gray fox is mainly distinguished from most other canids by its grizzled upper parts, strong neck and black-tipped tail, while the skull can be easily distinguished from all other North American canids by its widely separated temporal ridges that form a U-shape. There is little sexual dimorphism, save for the females being ever so slightly smaller than males. The gray fox ranges from 76 to 112.5 cm (29.9 to 44.3 in) in total length. The tail measures 27.5 to 44.3 cm (10.8 to 17.4 in) of that length and its hind feet measure 100 millimetre. It weighs 3.6 kilogram. It is readily differentiated from the
red foxThe red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...
by the lack of "black stockings" that stand out on the latter.
The gray fox's ability to climb trees is shared only with the Asian
Raccoon dogThe raccoon dog , also known as the magnut or tanuki, is a canid indigenous to east Asia. It is the only extant species in the genus Nyctereutes...
among canids. Its strong, hooked claws allow it to scramble up trees to escape many predators such as the domestic dog or the
coyoteThe coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
, or to reach tree-bound or arboreal food sources. It descends primarily by jumping from branch to branch, or by descending slowly backwards as a house cat would do. The gray fox is nocturnal or
crepuscularCrepuscular animals are those that are active primarily during twilight, that is during dawn and dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is, thus, in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be active on a bright...
and dens in hollow trees, stumps or appropriated burrows during the day. Prior to European colonization of North America, the red fox was found primarily in boreal forest and the gray fox in deciduous forest, but now the red fox is dominant in most of the eastern United States.
Reproduction
The gray fox is monogamous. The breeding season of the gray fox varies geographically; in
MichiganMichigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, the gray fox mates in early March, in
AlabamaAlabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, breeding peaks occur in February. The gestation period lasts approximately 53 days. Litter size ranges from 1 to 7. Kits begin to hunt with their parents at the age of 3 months. By the time they are 4 months old, the kits will have developed their permanent dentition and can now easily forage on their own. The family group still remains together until autumn when the young reach sexual maturity and then disperse.
Diet
The gray fox is a solitary hunter and is largely
omnivorousOmnivores are species that eat both plants and animals as their primary food source...
. It frequently preys upon the
Eastern CottontailThe eastern cottontail is a New World cottontail rabbit, a member of the family Leporidae. It is one of the most common rabbit species in North America.-Distribution:...
(
Sylvilagus floridanus) in the eastern U.S., though it will readily catch
voleA vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, smaller ears and eyes, and differently formed molars . There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America...
s,
shrewA shrew or shrew mouse is a small molelike mammal classified in the order Soricomorpha. True shrews are also not to be confused with West Indies shrews, treeshrews, otter shrews, or elephant shrews, which belong to different families or orders.Although its external appearance is generally that of...
s, and
birdBirds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. In California, the gray fox primarily eats rodents, followed by lagomorphs, e.g. Jackrabbit,
Brush RabbitThe Brush Rabbit , or Western Brush Rabbit, is a species of cottontail rabbit found in western coastal regions of North America, from the Columbia River in Oregon to the southern tip of the Baja California peninsula...
, etc. Fruit is an important component of the diet of the gray fox and they seek whatever
fruitIn broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s are readily available, generally eating more vegetable matter than does the
Red FoxThe red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...
(
Vulpes vulpes).
Subspecies
There are 16 subspecies recognized for the gray fox. However, genetic analysis has not
- Urocyon cinereoargenteus borealis (New England)
- Urocyon cinereoargenteus californicus (southern California)
- Urocyon cinereoargenteus cinereoargenteus (eastern United States)
- Urocyon cinereoargenteus costaricensis (Costa Rica)
- Urocyon cinereoargenteus floridanus (Gulf states)
- Urocyon cinereoargenteus fraterculus ((Yucatan)
- Urocyon cinereoargenteus furvus (Panama)
- Urocyon cinereoargenteus guatemalae (southernmost Mexico south to Nicaragua)
- Urocyon cinereoargenteus madrensis (southern Sonora, south-west Chihuahua, and north-west Durango)
- Urocyon cinereoargenteus nigrirostris (south-west Mexico)
- Urocyon cinereoargenteus ocythous (Central Plains states)
- Urocyon cinereoargenteus orinomus (southern Mexico, Isthmus of Tehuantepec)
- Urocyon cinereoargenteus peninsularis (Baja California)
- Urocyon cinereoargenteus scottii (south-western United States and northern Mexico)
- Urocyon cinereoargenteus townsendi (northern California and Oregon)
- Urocyon cinereoargenteus venezuelae (Columbia and Venezuela)
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