Based on fossil record evidence, the last scenario seems most likely, which is further supported by the clear ecological and morphological differences between the two species.

The soles are heavily coated with fur that fully covers the pads, an adaptation to extremes of temperature in the desert,[7] that probably helps to distribute its weight and move easily on sand.

The larger ears, however, make them easy to distinguish from red and pale foxes, which also live in some of the same areas.

[8] Rüppell's fox is found in the deserts of North Africa south of the Atlas Mountains, from Mauritania and Morocco in the west to Egypt and Djibouti in the east.

It is also found in the Arabian Peninsula southwards from Syria, Israel, Jordan and Iraq, and as far east as Iran, Pakistan, and Afghanistan.

[10] It seems to avoid the extreme arid regions in the middle of the Sahara, being more abundant on the fringes, in mountain massifs and near oases.

[11] In Tunisia, the Rüppell's fox occurs in the Saharan habitat in Jebil National Park and possibly farther to the south-west.

[11] In Tunisia's Jebil National Park, recent research has shown a prodominently nocturnal activity pattern with very rare crepuscular observations preceding sunrise.

[14] They make a series of short barks during mating and, at other times, can also produce hisses, trills, and sharp whistles.

The size of the territories varies with the local terrain, but has been reported as around 70 km2 (27 sq mi) in Oman, with those of males being larger, on average, than those of females.

[7] In some regions, they are reported to be mainly insectivorous, especially feeding on beetles and orthopterans, while in others, small mammals, lizards, and birds form a larger part of their diet.

Plants eaten include grasses and desert succulents, along with fruits such as dates, and they have also been known to scavenge from human garbage.