Due to its isolated location far from the mainland, the Galapagos archipelago is home to just six mammal species. This unique ecosystem supports two types of bats and two types of rice rats, none of which you are likely to encounter on your journey. In contrast, two other species—Galapagos sea lions and Galapagos fur seals—will typically appear often during your Galapagos adventure. You may round out your mammal watching with views of bottlenose dolphins, while a sperm whale sighting would be a rarer treat.
Click on the links below to navigate to each species.
The most common native mammal you will see during your journey is the Galapagos sea lion, a subspecies of the Californian sea lion, which inhabits most islands. There are an estimated 50,000 individuals in the Galapagos. Territorial bulls can weigh up to 550 pounds and have exhibited aggressive behavior, including chasing swimmers from the water and biting people if harassed, so do not approach them too closely. On the other hand, females and pups are amiable and spirited and will often have fun swimming with snorkelers. Typically, sea lions live to approximately age 20. Females reach sexual maturity at age 5; males are capable of mating then, too, but usually do not do so until they are older. Dominant males patrol and guard particularly attractive beaches, territories that may contain up to 30 females. The dominant male will have mating access to these females, but only for as long as he is able to keep other males at bay. Defending a territory is very demanding work, and males may go for days without getting much food or sleep. After several weeks putting up this front, a harem-master may become weary and susceptible to defeat, causing him to lose his position to a new, well-rested male.
You will see endemic Galapagos fur seals less frequently than Galapagos sea lions, which they resemble only superficially. Upon closer inspection, fur seals look quite different from sea lions. They are smaller and have a wider and shorter head shaped more like a bear's. A fur seal’s ears are also more prominent, and their front flippers are larger than the sea lion's. Fur seals and sea lions share many similar mating and social behaviors. One main difference is that male fur seals tend to defend territory from the land, while male sea lions defend from the water.
During the 1800s, the sperm whale was hunted to the brink of extinction. The upwelling waters around the islands provide optimal feeding grounds for these marine mammals, which were hunted by the thousands as the industrial revolution demanded more whale oil in its early years. Once people began extracting oil from the earth, sperm whales were spared, but the history of the whaling industry left its mark on the Galapagos Islands. It is rare that visitors to the islands have an opportunity for an up-close encounter with a sperm