Atilax is fairly heavily built. Although it is more aquatic than any other mongoose, it is the only one with toes that completely lack webbing. This feature may be associated with the habit of feeling for aquatic prey in mud or under stones. There are five digits on each limb, the soles are naked, and the claws are short and blunt. The anal area is large and naked, and there is a narrow, naked slit between the nose and the upper lip.
Females usually have two pairs of mammae.
Favored haunts are marshes, reed-grown streambeds, and tidal estuaries. Grassy patches and floating masses of vegetation often serve as feeding places and as dry resting spots. Like other mongooses, Atilax does little or no climbing but does run up leaning tree trunks or other inclines easy of access. It is an excellent swimmer and diver. When hard pressed, it submerges, leaving only the tip of the nose exposed for breathing.