Along with the previously mentioned thick underfur, fur seals are distinguished from sea lions by their smaller body structure, greater sexual dimorphism, smaller prey, and longer foraging trips during the feeding cycle.
 The physical appearance of fur seals varies with individual species, but the main characteristics remain constant.
 
Fur seals are characterized by their external pinnae, dense underfur, vibrissae, and long, muscular limbs.
 They share with other otariids the ability to rotate their rear limbs forward, supporting their bodies and allowing them to ambulate on land.
 In water, their front limbs, typically measuring about a fourth of their body length, act as oars and can propel them forward for optimal mobility.
 The surfaces of these long, paddle-like fore limbs are leathery with small claws.
  Otariids have a dog-like head, sharp, well-developed canines, sharp eyesight, and keen hearing.
 
They are extremely sexually dimorphic mammals, with the males often two to five times the size of the females, with proportionally larger heads, necks, and chests.
 Size ranges from about 1.5 m, 64 kg in the male Galapagos fur seal (also the smallest pinniped) to 2.5 m, 180 kg in the adult male New Zealand fur seal.
 Most fur seal pups are born with a black-brown coat that molts at 2–3 months, revealing a brown coat that typically gets darker with age.
Some males and females within the same species have significant differences in appearance, further contributing to the sexual dimorphism.
 Females and juveniles often have a lighter colored coat overall or only on the chest, as seen in South American fur seals.
 In a northern fur seal population, the females are typically silvery-gray on the dorsal side and reddish-brown on their ventral side with a light gray patch on their chest.
 This makes them easily distinguished from the males with their brownish-gray to reddish-brown or black coats.
Along with the previously mentioned thick underfur, fur seals are distinguished from sea lions by their smaller body structure, greater sexual dimorphism, smaller prey, and longer foraging trips during the feeding cycle.  The physical appearance of fur seals varies with individual species, but the main characteristics remain constant.  
Fur seals are characterized by their external pinnae, dense underfur, vibrissae, and long, muscular limbs.  They share with other otariids the ability to rotate their rear limbs forward, supporting their bodies and allowing them to ambulate on land.  In water, their front limbs, typically measuring about a fourth of their body length, act as oars and can propel them forward for optimal mobility.  The surfaces of these long, paddle-like fore limbs are leathery with small claws.   Otariids have a dog-like head, sharp, well-developed canines, sharp eyesight, and keen hearing.  
They are extremely sexually dimorphic mammals, with the males often two to five times the size of the females, with proportionally larger heads, necks, and chests.  Size ranges from about 1.5 m, 64 kg in the male Galapagos fur seal (also the smallest pinniped) to 2.5 m, 180 kg in the adult male New Zealand fur seal.  Most fur seal pups are born with a black-brown coat that molts at 2–3 months, revealing a brown coat that typically gets darker with age. Some males and females within the same species have significant differences in appearance, further contributing to the sexual dimorphism.  Females and juveniles often have a lighter colored coat overall or only on the chest, as seen in South American fur seals.  In a northern fur seal population, the females are typically silvery-gray on the dorsal side and reddish-brown on their ventral side with a light gray patch on their chest.  This makes them easily distinguished from the males with their brownish-gray to reddish-brown or black coats.
Fur seal