Ross seals are the smallest seals of the Antarctic region, with a thick neck and a slender body. Members of this species have short body hairs, with the shortest hair and vibrissae of any phocid. They are dark brown on their dorsal surface and their ventral surface is silvery; spots and streaks frequently mark the head, neck, and flank. During the summer, unmoulted seals are tan to brownish, with moult occurring in January. Males average smaller than females, from 168 to 208 cm long and weighting 129 to 216 kg. Females measure from 190 to 250 cm long and weigh between 159 and 204 kg. Ross seals can easily be distinguished from closely related seals by their disproportionately large eyes (70mm in diameter). The large eye sockets in the skull are a good character by which a Ross seal can be identified (King 1990).
Range mass: 150 to 215 kg.
Range length: 168 to 250 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger