Hoary Fox: The Fox That Survives in the Brazilian Cerrado

The hoary fox is known for its small size and preference for solitude or small groups.

By Bertie Atkinson - Science & Biology Editor
Hoary Fox
Hoary Fox
  • Hoary foxes are nocturnal omnivores with a miniature fox-like appearance.
  • They face threats from maned wolves and human activities.
  • They may consume fruit, insects, and even small vertebrates.

Lycalopex vetulus, often known as the hoary fox, belongs to the family of canids and is an omnivore. The Cerrado ecosystem is home to this Brazilian endemic animal. It has a short nose, big ears, and little teeth, making it seem like a miniature fox. Gray, brown, blackish, yellowish, and reddish all make appearances on their coats. The hoary fox either prefers to be alone or in tiny groups of its own kind.

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Hoary Fox at a Glance

Engraving of a hoary fox by J. G. Keulemans, 1890.
Engraving of a hoary fox by J. G. Keulemans, 1890.

A hoary fox is characterized by being more active at night. Its primary food source is insects; however, it may occasionally eat small vertebrates and fruit. The female gives birth to one to five young (often two or four) after less than two months of gestation, typically between the months of July and October. The IUCN considers this species to be near-threatened because of declining habitat, canine predation, human persecution, sickness, and deaths from car accidents.

The hoary fox is a slim and swift creature, able to twist and leap with ease while on the go.

Canis vetulus, the original name for the hoary fox, was coined in 1842 by Danish palaeontologist and naturalist Peter Wilhelm Lund. The animal was later classified as a member of the subgenus Cabrera or in the genus Lycalopex (“wolf fox”) or Pseudalopex (“false fox”) for the South American fox. W. Christopher Wozencraft’s (2005) taxonomical designation of the creature as a member of the genus Lycalopex is still widely accepted today.

Evolution of the Hoary Fox

There are a total of six canine species in this genus that resemble the American “false” foxes (including the Pampas Fox). They share only superficial similarities owing to convergent evolution. The hoary fox is the oldest member of a genus; the common ancestor of the six species existed a million years ago. For comparison, the first real foxes arrived in North America in the late Miocene, some 9 million years ago. Here is the evolutionary branching:

  • Lycalopex
    • Lycalopex vetulus
      • Lycalopex sechurae
        • Lycalopex fulvipes
        • Lycalopex gymnocercus
        • Lycalopex griseus
        • Lycalopex culpaeus

What is a Hoary Fox?

hoary fox (Lycalopex vetulus)
(Photo: Carlos Almeida, CC BY 3.0)

The hoary fox is a smallish, graceful animal with long, thin ears (about 2.5 to 3 in) and a short, pointed nose. It may weigh anything from 5.5 to 9 lb, and its length can span anywhere from 20 to 28 in. Tail length varies between 10 and 15 inches. The range is 13–15 in for shoulder height. There is either no or very little sexual size dimorphism in hoary foxes, as females are somewhat smaller than males.

In hoary foxes, the color of the coat might vary. The undersides are often yellow or hazel, while the back and sides are light gray. While the neck is white, the lower jaw and tail’s base and tip are both dark and nearly black.

Males may have a black stripe that extends from their neck to their tail. A shadowy area sits above the tail gland. The insides of the legs and the ears have a ruddy color. There have been reports of very black, almost melanized hoary foxes. The average length of their skulls is 4–5 inches, and they are made of delicate bones.

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Skull and jaw of the hoary fox (Lycalopex vetulus) by St. George Jackson Mivart, 1890.
Skull and jaw of the hoary fox (Lycalopex vetulus) by St. George Jackson Mivart, 1890.

The hoary fox supports the largest tympanic bulges in South American canids, which points to the significance of hearing in foraging. Although hardly noticeable, the sagittal crest is actually exclusive to male hoary foxes. Just like dogs, the hoary fox has a grand total of 42 teeth.

Because of their diet of tiny food (insects), their dentition typically consists of short canines and, in contrast, somewhat broad molars. The hoary fox is smaller and slenderer than the crab-eating fox, which it shares its habitat with, and has a longer neck and thicker, longer hair. Identifying a hoary fox based on its coat color is not sufficient.

Where Does the Hoary Fox Live?

Hoary foxes can only be found in Brazil. Its native range includes the Brazilian states of Bahia, Goias, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Piaui, Sao Paulo, Tocantins, Rondonia, Ceara, Maranhao, and Brasilia Distrito Federal.

They favor locations with little vegetation, such as the cerrado, where they make their home. During the flood season, they may be found in open, dry sections of the Pantanal, despite their preference to avoid wetter environments. Plantations of eucalyptus and rubber trees (hevea) are among the man-made environments where they have been seen. They may be found living at an elevation of 3,600 feet.

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Hoary fox cubs in Bacury Lodge, Anhembi - State of São Paulo, Brazil.
Hoary fox cubs in Bacury Lodge, Anhembi – State of São Paulo, Brazil. (Photo: Steven Whitebread, CC BY 4.0, cropped)

Their Diet

The hoary fox is nocturnal, although it sometimes ventures out during the day. Depending on the species, the average home range size is anything from 45 to 1130 acres. Their temperament is mild, yet they may become violent in defense of their young.

The hoary fox is an omnivore that mostly eats fruit and insects. Termites, beetles, grasshoppers, and ants are the most common types of insects. Small animals (rodents), birds, reptiles, and invertebrates round out the diet. The diet consists mostly of termites and small animals during the dry season and fruit and other insects during the wet season. Syntermes termites are the most prevalent kind of termite they consume.

Creating a New Life

Because of its monogamous nature, this species of canid forms lasting partnerships. About 50–60 days are needed for a successful pregnancy. Typically, litters appear between the months of July and October. The average number of puppies born in a litter is three. Vacant armadillo burrows are used by females as dens. Mothers typically spend four months (and sometimes up to six) tending to their kids. They bark at potential threats in an effort to scare them away.

Males are supposed to help with childrearing. Typically, adolescents become self-sufficient between the months of April and May. They choose to live in areas that are geographically near where they originated. Parent-offspring rivalries over territory have been documented during the dry season. One hoary fox has lived for eight years in captivity, but nobody knows how long they can survive in the wild.

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The Threats Hoary Foxes Face

The maned wolf and the crab-eating fox are sympatric predators that might threaten the hoary fox. Although the maned wolf is much bigger than the crab-eating fox, they do not compete for food since their diets are so different. In central Brazil, 0.3–4% of crab-eating fox feces have been discovered to include the remains of the hoary fox.

The American cougar may serve as a scavenger on rare occasions. There has been no evidence of predation by raptors or other felids (such as jaguars and ocelots). Roadkill, domestic dog attacks, poisoning, and shooting are among the other reasons for mortality.

The hoary foxes were found to host various illnesses and parasites, including scabies, Trypanosoma cruzi, and Angiostrongylus vasorum. Blood-sucking vampire bats can infest this animal as much as they infect humans, but they won’t kill the animals.

Is Their Population Healthy?

This species is currently considered to be “Near-Threatened” by the IUCN. Between 10,000 and 20,000 adults make up the entire population of the hoary fox. Over the last decade, there has been at least a 10% drop in this number.

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The greatest dangers come from human activities, such as habitat degradation. Historical perspectives on the Cerrado, the almost sole home range of these carnivores, have been that it is an unproductive place that has to be farmed or searched for human purposes.

Over the last two decades, this region has seen a growth in the number of towns, the harvesting of wood, the cultivation of pastures and fields, and the construction of new transportation infrastructure. Because of these factors, habitats for indigenous animals, such as the hoary fox, have been destroyed or fragmented.

In Brazil, it is illegal to hunt this animal. Many foxes in the population like living in protected places such as national parks.