Island Fox

Photograph by Chien Lee.

### Other

Coast fox, short-tailed fox, island gray fox, channel island fox, channel islands gray fox, California channel island fox, insular gray fox

## Information

### Length

19–19.5 in. (head to body), 4.5–11.5 in (tail)

### Diet

Omnivore; birds, mammals, amphibians, reptiles, insects, mollusks, fruit

## Subspecies

U. littoralis littoralis, U. santarosae, U. santacruzae,
```
U. dickeyi, U. catalinae, U. clementae
```

The island fox is a small fox that is native to six of the eight Channel Islands of California (Santa Catalina, San Clemente, San Nicholas, San Miguel, Santa Cruz, and Santa Rosa). Its specific epithet *littoralis* means "belonging to the seashore". There are six subspecies, each unique to the island it inhabits. These creatures are found nowhere else in the world.

## Physical Description

The island fox is possibly the smallest fox in North America—and is one of the smallest canids in the world—averaging slightly smaller than *Vulpes velox* and *Vulpes macrotis.* The largest subspecies (*Urocyon littoralis catalinae*) occurs on Santa Catalina Island, and the smallest subspecies (*Urocyon littoralis santacruzae*) occurs on Santa Cruz Island. The species shares a strong resemblance to *Urocyon cinereoargenteus.*

Males are slightly larger than females.

"The fur is grayish-white and black with cinnamon underfur on the dorsal side, and with pale white, yellow, and rusty-brown on the ventral surface. The chin, lips, nose, and areas around the eyes are lined in black while the sides of the rostrum are grey. The ears, neck, and sides of the limbs are cinnamon-colored. The tail has a contrasting thin black stripe on the dorsal side with a mane of stiff hairs. The underside of the tail is a rusty color," [2]. Generally, fur color may differ among the six islands and be highly variable among individuals. The island foxes molt once a year during the fall season, between August and November. During that length of time, the fur coat fades significantly in color and the fur tips curl at the ends. For pups, during their first molt they become woolly and are darker in color compared to adults.

Adolescent foxes tend to have a paler but thicker dorsal fur coat. Their ears are darker in color in comparison to adults.

## Habitat

Varies depending on the island, but not specifically, the species depends upon complex layers of vegetation with a high density of woody fruity shrubs. More specifically, each island supports biomes such as valley and foothill grasslands, coastal sage/scrub, coastal bluff, sand dune areas, island chapparral, southern coastal oak woodland, island woodland, southern riparian woodland, pine forests, and coastal marshes. Island foxes live happily within all of these habitats.

## Reproduction

Due to the severe lack of sexual dimorphism (aside from a minor size difference) and a relatively equal ratio in sexes of each population, the species typically forms monogamous breeding pairs. These pairs are usually seen together in January to find a den location. These dens are seldom made by the foxes themselves, and include types such as ground holes, hollow trees, rock piles, shrubs, caves, and man-made structures. However, if the mother is unable to find a sufficient shelter, she will dig a small hole. Breeding occurs during the months of late Febuary to early March.

After mating, gestation in females takes place in 50-63 days, and pups are usually born from late April through early May. Though the average litter is 2-3 pups, it can range from 1-5 pups. Pups are born blind and incredibly small, with short dark brown hair. They depend on their mother for milk during the first 7-9 weeks. After being weaned, they emerge from the den approximately a month after their birth and forage for food alongside their parents. They're much furrier and still considerably darker at this age. Both parents have been seen caring for the pups.

Pups grow up notably fast, as they remain with their parents during the summer before becoming independent by September. Around this time, their pelts begin to shift into their adult coloration. They reach sexual maturity by 10 months old, and females often breed around one year of age. While females often stay around their birth den, males leave to go set up their own territories.

## Behavior

Island foxes are primarily nocturnal, but are known to be active during both day and night. Activity peaks around dusk and dawn as they look for food. However, they are more active during the day in summer compared to winter.

They are somewhat solitary, aside from those who have obtained a mate.

Each individual fox have a territory that they mark with urine and feces. While they act aggressive toward strangers and intruders, mates tend to have overlapping territories. Mates share mutual grooming times within this linked territory. Territorial disputes—when they do occur—between two stranger foxes, can be serious and fatal. The results of these violent fights can include ripped and torn ears, leg wounds, and death.

The island fox are docile and playful creatures, and are completely unafraid of humans due to lack of regular and negative contact. Instinctively, they may at first show aggressive behavior, but they quickly become more affectionate and relaxed soon after. They're also known to be naturally curious.

## Communication

### Vocal

Barking is a common form of communication, most often heard at night. They also bark to warn off foxes that are too close to another's territory.

An island fox growls to show displeasure or as a warning. Growling is often used by a fox appearing dominant to another, more submissive fox.

Whining is only used in distress or in submissive displays.

### Physical

In dominance displays, island foxes can be seen staring/forcing eye contact and flattening the ears to appear larger and more intimidating. Body posture, such as lifting the body or arching the spine is often used. Facial expressions are also a common factor.

When being submissive, foxes will lower the head and crouch down. They'll purposefully avoid eye contact, flattening the ears to appear smaller. Sometimes, they'll lick the maw of the more dominant fox to appease them from acting aggressively or violently.

## Terminology

Young are referred to as **pups** or **kits**.

Males are referred to as **males**.

Females are referred to as **females**.

## Food Habits

Though island foxes are strictly omnivorous, specific food items vary between each subspecies. The main categories they go for are insects, deer mice, lizards, birds, garden snails, fruits, as well as mollusks, crabs and some amphibians.

The amount of each food item they consume depends on the island a subspecies may inhabit. This especially goes for the types of fruit they feed on.

On all six islands, beetles are a primary source of nutrients within their insect diet. Earwigs are also a primary source, though *Urocyon littoralis clementae* find them only important during the spring season, and *Urocyon littoralis catalinae* only during fall and winter.

Island foxes from all of the islands have been caught hunting and catching snakes, but there was no evidence of snake remains in fox scat in 2009.

Certain subspecies are also more prone to scavenging from carrion.

## Survival Adaptations

Island foxes can run quickly over grasslands and hills to pursue and catch their prey. To forage for other food up in the trees, they've evolved the ability to turn their front paws inward to give them excellent skills in climbing. They've been observed climbing these trees for fruit, as well as to reach bald eagle nests to scavenge for eggs and dropped fish.

They have excellent vision, adapted both for day and night. As well as this, their sense of smell is precise, helping them in finding food, identifying other island foxes, and to define the lines between territories.

## Sources

1. https://www.nps.gov/chis/learn/nature/island-fox.htm
2. http://animaldiversity.org/accounts/Urocyon\_littoralis/
3. https://www.nytimes.com/2016/04/26/science/channel-island-foxes-least-genetic-diversity.html?\_r=0
4. https://en.wikipedia.org/wiki/Island\_fox
5. http://www1.islandfox.org/p/about-island-fox.html
6. http://www.iucnredlist.org/details/22781/0