Fur Seal or Sea Lion?

The Galapagos fur seal and the Galapagos sea lion can be difficult to tell apart. We’ve compiled this list of top tips, with the expert advice from Galapagos sea lion expert, Professor Fritz Trillmich, to help you try and spot the fur seals from the sea lions. We hope this will help you either on your trip to Galapagos, or with identifying your photos when you get back!

The Galapagos fur seal and the Galapagos sea lion are actually quite closely related, and come from the same family: “Otariidae” which means “eared seal”.

• The Galapagos fur seal belongs to a genus of fur seals called Arctocephalus (or Arctophoca), meaning bear-headed.
• The Galapagos sea lion belongs to the genus Zalophus which contains 2 extant sea lion species, and previously contained the Japanese sea lion which went extinct in the 1970’s.

So here’s what to look out for if you’re finding it tricky to tell your fur seal from your sea lion:

 1). Size

The overall size of the animal is a great starting place for telling them apart. The Galapagos fur seal is a lot smaller than the Galapagos sea lion. An adult female fur seal weighs 27-33kg, whereas an adult female sea lion weighs between 55-75kg. The sea lion also has a greater body length, especially noticeable from behind the front flippers. This makes the fur seal appear stockier than the sea lion. In both species, the males are approximately twice as big as the females.

2). Pelt

When the animals are out of the water and resting on dry land, their pelt is a good indicator of species. The fur seals have much thicker fur, which consists of a dense underfur and long guard hairs covering it. This fur has an agouti colour when dry, but turns black when wet. As they begin to dry on the shore, they may soon present goldish tinges. In contrast, the sea lion has a much smaller amount of underfur and are darker in colour.

Galapagos fur seal – Vanessa Green

3). Ears and eyes

The facial features are a good distinguishing feature of the Galapagos fur seal. They have larger, more bulbous eyes than the sea lion. Similarly the fur seal’s ears are more pronounced and tend to stick out more than the ears of the sea lion.

Left: Galapagos sea lions – Just Janza     Right: Galapagos fur seal – Roger Bates

4). Movement

Another way to tell the two species apart is by their movements, however this is a less useful method when identifying from photographs. When resting in the water, fur seals often adopt a head-down position with their hind flippers on the surface to allow them to watch for predators as they rest. However, both species have been known to rest floating on their sides as well. When observed on the shore, fur seals are usually found on rocky shores, where they climb and hop about. Sea lions, however, prefer to move on smooth surfaces. Their head and neck moves conspicuously from side to side as they go.

Left: sea lions on the beach – Fuller    Right: fur seals on lava rocks – Derek Haslam

5). Identifying a pup

This age class presents the greatest difficulties in distinguishing the species’. Both are born almost black in colour and become lighter with age. The best way to tell the pups apart is by using the eyes and ears, which show the same differences as the adults with the fur seal’s ears sticking our more, and their eyes much larger.

Galapagos sea lion – David Nelson

6). Distribution

Galapagos sea lions can be seen everywhere within the Archipelago, whereas fur seals are most likely to be seen by tourists around Isabela and Fernandina islands. The male fur seals are more vagrant than the females and can regularly be seen on Santiago and Bartholome islands, as well as on the southern parts of Floreana.

Thank you to Professor Fritz Trillmich for providing the identification tips for this blog piece. Professor Trillmich is a behavioural ecology expert from the University of Bielefeld in Germany, specialising in the pinnipeds of Galapagos.