Galapagos sea lions differ in color depending on sex and whether their coats are wet or dry. The area surrounding the eyes as well as the muzzle of both males and females are lighter in hue than the rest of the body. After being submerged in water, the bull's coat takes on a dark black hue. When dry, the coat is usually dark brown but can range from different shades of brown to gray. Once a bull reaches full maturity, the coat ceases to get any darker, and its back usually turns a light shade of gray. Mature females, adolescent males, and juveniles vary in shade from light brown to tan. Pups experience their initial molt around five months of age, losing the darker coat they were born with.
Galapagos sea lions are sexually dimorphic, with males larger than females. Males tend to have a thicker, stouter neck, shoulders and chest than females, and adult canines are substantially larger and stronger in males. As males grow, their sagittal crest develops more rapidly, leaving a pronounced protrusion on their head. After the male reaches full maturity, the crest ceases to grow, and its forehead becomes steeper due to the pronounced ridge that forms at the back of its eyes. Female Galapagos sea lions have a more elongated, sleek neck and a wider upper body relative to their body size. Females, along with immature sea lions, do not have sagittal crests; their forehead is less defined and adolescents foreheads are almost nonexistent, with virtually a flat head. Galapagos sea lions can weigh between 50 and 250 kg and are often 150 to 250 cm in length.
Range mass: 50 to 250 kg.
Range length: 150 to 250 mm.
Sexual Dimorphism: male larger; sexes colored or patterned differently; sexes shaped differently