Question: how far can a fox dig?
Answer: According to Vladimir Heptner and Nikolai Naoumov, in their 1988 Mammals of the Soviet Union, foxes dig downwards at an angle of 40 to 45-degrees, creating tunnels 15 to 20 cm (8 in.) in height and 25 to 30 cm (12 in.) wide, depending on the soil type; entrances are oval or rounded, 30 to 40 cm (16 in.)