Fennec fox

The fennec or desert fox (Vulpes zerda) is a species of fox in the genus Vulpes. It is the smallest of all wild dogs and inhabits the sandy deserts of North Africa. The species displays numerous adaptations to the desert climate, such as small body size, hairy soles, and large ears that serve to regulate heat. The fennec is nocturnal and crepuscular and is omnivorous, eating invertebrates and small vertebrates as well as fruits and tubers.

Fenneks usually live in pairs; the usually two to five young per litter are born in March and April. During the gestation and suckling period, the male cares for and protects the female and the litter. The burrow of the fennec is usually simple and is usually dug in loose sand, only taking on more complex forms in firmer subsoil. The fennec's closest relative is the Afghan fox (Vulpes cana), which lives in the Arabian Peninsula, Iran, and Afghanistan. Although fennecs are regularly trapped for their fur or for tourist displays, the population is not considered threatened. The IUCN classifies the species as Least Concern (not endangered). The fennec has been used as a source of food and fur by the people of North Africa since the Neolithic period and has also been kept as a pet since the 20th century, particularly in North America.

Features

Physique and physiology

The Fennek is the smallest of all dog species and has very large ears. Its head-torso length is 333-395 mm, the tail becomes 125-250 mm long. Its birth weight is between 80 and 187 g, adult weight is 1.0 to 1.5 kg. The ears account for 20% of the body surface and grow to 86-104 mm in length. This makes them proportionally larger than in all other dogs. The muzzle and legs are slender and delicate. The skull is similar in proportions to that of other Vulpes species, but has very large tympanic cavities, a typical feature of desert dwellers. The dental formula is I 3/3 - C 1/1 - P 4/4 - M 2/3, so the Fennek has a total of 42 teeth. They are smaller and narrower than in other species of the genus. The penis bone (baculum) is 3 mm wide and comparatively long at 31-36 mm. 

The coat is sandy brown with a beige, reddish or grey tinge. The underside of the body is lighter than the upper side. The ears have a dark back, their inner side and their edges are white furred. The eyes are relatively large and dark, with a dark line extending from the inner corner down to the muzzle and framing it. A shorter line runs from the outer corner of the eyes towards the cheeks. The thighs are reddish in individuals from the northern part of the range. In animals from the south they are white. The coat is very dense and long. The hair on the toes extends beyond the soles, forming an insulating pad for the feet. The tail is densely hairy, its tip and the area around the vial gland are dark in color. Females have three pairs of teats. The fennec changes its coat from summer to winter, with the summer coat being slightly shorter and lighter than the winter coat. Juveniles show similar fur markings to adults, but are lighter in color and have little to no red in their fur. The dark facial markings are only faintly pronounced in them. 

The fennec's kidneys are designed to filter highly concentrated urine while using as little water as possible. The fennec's metabolic rate is very low, 33% below what animals of its size usually have. Its heart is 40% smaller than would be expected for its body size. Below 35°C outside temperature, the fennec breathes at 23 puffs per minute. However, if this value is exceeded, the breathing rate can increase up to 690 breaths per minute. The blood vessels in the ears and soles of the feet dilate in heat to release as much heat as possible to the outside.  The Fennek has 2n = 46 chromosomes.

vocalizations and communication

The voice of the fennec is high and resembles that of small domestic dogs. Its call repertoire is extensive and sometimes melodious. Weak barking serves as a warning call against predators, purring reminiscent of domestic cats as an expression of well-being. As a threatening gesture, the Fennek emits a high-pitched yelp. Partners, parents or other individuals to whom the animals have a positive relationship - in the case of captive fennecs this can also be humans - are greeted with a squeal. 

Two fennecs at Tokyo Zoo. Details of the coat pattern as well as the ear and toe hair can be seen well.

Distribution

The range of the fennec covers the entire Sahara and is limited by areas with a temperate or humid climate. The northwestern limit of distribution is formed by the southern foothills of the Atlas Mountains, while the species range in Tripolitania extends almost to the coast. In Egypt, it is roughly bounded by the Nile, but extends north to the northwestern Sinai Peninsula. In Sudan, the range also includes areas farther east than in Egypt, such as the Nubian Desert. Overall, however, the fennec is absent along the coastal region to the Red Sea. In Mauritania and Morocco, the fennec occurs as far as just off the Atlantic coast. The southern limit of the range is marked by the northern Sahel, where the Fennek occurs up to about 14°N.

It is questionable whether there are or were occurrences of the fennec on the Arabian Peninsula. Several sightings have been reported from there, but some of them were only footprints in the sand or ruffed foxes (V. rueppelli), which were thought to be fennecs. The IUCN does not assume that the species occurs east of the Sinai, other authors consider it at least possible.

Range (green) of the fennec. The species range includes the entire Sahara, but excludes the humid and semi-arid regions along the Mediterranean coast, the Red Sea and the Sahel.