UROCYON CINEREOARGENTEUS: CHARACTERISTICS, HABITAT, BEHAVIOR - BIOLOGY - 2025

For its part, the species Urocyon cinereoargenteus was first described by Schreber in 1775, as Canis virginianus. Currently 16 subspecies of gray fox are recognized.

Habitat and distribution

Habitat

The silver fox lives preferably in places with high or dense vegetation in temperate and tropical zones, such as deciduous forests, shrubs and scrubs, although it can also inhabit arid and semi-arid zones. It builds its burrow in hollow tree trunks, between rocks, or in holes in the ground.

Distribution

Urocyon cinereoargenteus is the only canid species that is distributed both north and south of the American continent. It lives from southern Canada (from Manitoba to southeast Quebec) to Venezuela and Colombia, in northern South America, except in some regions of the United States and Central America.

Gray fox Urocyon cinereoargenteus. Taken and edited from: Photo by David J. Stang.

Despite being a single species, there is a geographical segregation of the 16 known subspecies, with U. cinereoragenteus borealis as one of the northernmost subspecies and U. cinereoargenteus venezuelae as the southernmost species.

Reproduction

Gray foxes are dioecious organisms with a slight sexual dimorphism, the males being slightly larger than the females. They have a maximum longevity of 16 years in captivity. Females reach sexual maturity a few days before males, who mature at approximately one year of age.

The organisms of this species are solitary, except in the breeding season where they are in pairs, which remain together during the breeding season. After which it is difficult to see them together although they return to form a couple in the next reproductive season, that is, they are monogamous. The reproductive cycle of this species is annual.

The reproductive season will vary depending on the location, but generally begins in December or January and ends in April. After a brief courtship and copulation, there is a gestation period that lasts 53 to 57 days and the female gives birth to a litter of variable size, although generally there are four cubs that weigh about 95 grams each.

Parturition occurs in a burrow made up of a hollow log, a crevice between rocks or a hole dug by the female herself. The female suckles the cubs for almost two months. The male collaborates in the rearing of the cubs for four months, when they are capable of hunting and defending themselves and abandon the mother.

Feeding

Urocyon cinereoargentus is an omnivorous species, that is, its diet includes both material of animal origin and plant origin. Foods of plant origin are represented mainly by fruits, seeds and roots. These can be the main components of the diet during the spring months.

The animal component of the diet, for its part, is quite varied and generally includes species that hunt alone. Its main prey are rodents and lagomorphs, such as rats, mice, hares and rabbits of various species. It also captures shrews, birds and reptiles, mainly lizards.

Among the invertebrate species, are part of the diet of U. cinereoargenteus: beetles, butterflies, moths, grasshoppers. Sometimes the gray fox uses carrion to complete its diet. It also consumes organic waste when it lives near human settlements.

Behavior

Although in general the canids show a gregarious behavior, the gray fox is a rather solitary species, showing a tendency to group together only during the reproductive season, when small groups formed by the couple and their young can be observed.

The young leave the family group when they reach sexual maturity. Males are more prone to dispersal than females, who tend to stray less from the family group and eventually return during the first weeks.

It is a shy species that shuns the noise and the presence of the human being. It is mainly nocturnal. During the day it is hidden in its burrow and is activated to hunt, move or find a mate during the hours of the night.

During the hunt he does not form herds, but acts equally alone. If the result of the hunt is abundant, the fox stores the food in one place, which it marks with urine to be able to locate it later more easily.

If threatened, the gray fox is able to climb trees to escape its enemy, an ability that only shares with the raccoon dog within the group of canids. It can also climb in search of food.

Gray fox Urocyon cinereoargenteus. Taken and edited from: California Department of Water Resources.

Main threats and current status

According to the International Union for Conservation of Nature (IUCN), Urocyon cinereoargenteus is located in the Least Concern category of the red list of threatened species.

It is a species with a wide distribution and despite the fact that in some localities its populations have suffered significant declines, in general terms the population has remained relatively stable in recent decades.

The main threat facing this species is habitat loss and degradation due to urban and rural expansions. Interspecific competition for food with domestic animals, mainly cats that have gone wild, is a growing problem for the survival of the gray fox.

Despite the fact that its fur is not highly prized, it is eventually hunted for it. It is also considered a pest in some localities where the expansion of human activities have increased human interactions with this species that can attack poultry for food.

The capture of organisms to keep them as exotic pets and the increase in diseases due to contact with domestic species are two other factors that also affect gray fox populations.

References

1. Gray fox. On Wikipedia. Recovered from: en.wikipedia.org.
2. EK Fritzell & KJ Haroldson (1982). Urocyon cinereoargenteus. Mammalian Species.
3. CA Bozarth, SL Lance, DJ Civitello, JL Glenn & JE Maldonado (2011). Phylogeography of the gray fox (Urocyon cinereoargenteus) in the eastern United States. Journal of Mammalogy.
4. Gray Fox - Urocyon cinereoargenteus. In NatureWorks. Recovered from: nhpbs.org.
5. J. Servín, A. Bejarano, N. Alonso-Pérez & E. Chacón (2014). The size of the home range and habitat use of the gray fox (Urocyon cinereoargenteus) in a temperate forest of Durango, Mexico. Therya.
6. AnAge entry for Urocyon cinereoargenteus. In AnAge: The animal aging and longevity database. Recovered from: genomics.senescence.info.