The world of Pinnipeds (carnivorous, fin-footed, semi-aquatic marine mammals) is divided into walrus (odobenidae), seals (phocidae) and sea lions (otariidae). The Galápagos Fur Seal however is not a true seal. It would be more accurately described as a Galapagos fur sea-lion. So why call it a seal and what's the difference?
Galápagos Fur Seals, like all similar fur seals are not actually true seals (phocidae). Instead, they are the smallest members of the otariidae family, meaning they have external ear flaps, like their larger distant-cousin, the Galápagos Sea Lion.
So why is the Galápagos Fur Seal commonly called a seal and not a sea lion? Primarily, it’s the outward observable differences in shape and size. Galápagos Sea Lions have pronounced longer necks and dog-like heads with pointy snouts, whereas Galápagos Fur Seals have thick, shorter necks, shorter muzzles and larger eyes. The other major difference being sea lions have a single coat consisting of short coarse hair, whereas the fur seals have a dense under layer of fur plus a coat of coarse hair. Locally they are referred to as “dos pelos” meaning two coats or skins.
Galápagos Fur Seals are primarily solitary, preferring rocky coastlines, whereas Sea Lions are far more social, living together in large herds or "rafts", and prefer to haul out of water on sandy beaches. Both Galápagos Fur Seals and Sea Lions give birth to a single pup at a time, and feed on fish and cephalopods. Fur Seals can dive extraordinarily deep, and have been observed at depths exceeding 550 feet. Despite this, both species are extremely susceptible to the effects of El Niño, where warm waters decrease the sardine population and push the thermocline and their cephalopod (squid, cuttlefish, octopus) food source far deeper.
Despite being hunted to near extinction, Galápagos Fur Seal populations are now stable and rebounding. Galápagos Sea Lions however are still at risk. Due of their equatorial location and absence of seasonal changes in daylight, Galápagos Sea Lions experience an unusually long breeding season, spanning May through January. As a result, Galápagos Sea Lions, unlike sea lions elsewhere, do not have synchronized pregnancies, which results in a higher infant mortality.
Visitors to the Galápagos will have ample opportunity to observe and interact with Sea Lions throughout the islands. Fur Seals can be best seen on the at Prince Philip's Steps on Genovesa (Tower) Island on the eastern itinerary, and at Puerto Egas on Santiago Island on the western itinerary.