It is pale brown or grayish coloured, with eight wide, dark stripes on its back and sides.

[2] With a few exceptions, the majority of records of G. grandidieri come from a narrow zone at the western edge of the Mahafaly Plateau in the Parc National de Tsimanampetsotsa, making it the Madagascan carnivore with the smallest range.

[3] The species is sympatric with two other carnivores, the fossa (Cryptoprocta ferox) and the introduced Indian civet (Viverricula indica).

It is presumed that the distribution of this mongoose was notably broader and the proportion of prey types different in earlier times than today.

Grandidier's mongoose must have adapted to dryer conditions, which have resulted in its very limited distribution and the exploitation of notably small prey.