The South American fur seal has a dark grey coat of fur. The males of the species are almost entirely this color, though they may have grey or tan, grizzled markings. The females and subadult males have lighter grey or tan coloring on the chest and muzzle, and may have rust-brown or medium grey fur on their undersides. The muzzle is flat-topped and pointed, with a medium-sized nose. The nostrils are forward-facing and the nose extends past the mouth. The ear pinnae are long and prominent, and the vibrissae of adults are creamy white and of relatively short length. Adult males are larger than females, with thicker necks and larger shoulders. Males also develop manes of longer guard hairs on their heads and shoulders. Size of the seals varies based on region, but on average, adult males measure up to 2 m long and weigh 150–200 kg and females measure up to 1.5 m long and weigh 30–60 kg. Newborns are 60 to 65 cm and 3.5 to 5.5 kg.