Marine Mammals Archives - Page 4 of 4 - Oceana


Reproductive output, however, is quite low – with females giving birth to only one calf, every other year – and the gestation period is 11 months, longer than most land mammals, including humans. Lifespan is also low, with individuals likely living no longer than approximately 25 years. Vaquitas are predatory and eat a variety of Gulf of … Read more

Southern Elephant Seal

The southern elephant seal is one of two living species of elephant seals. These two species get their name from the trunk-like nose that males develop as they become sexually mature. Only the strongest, most dominant males win the right to mate with females, and ninety percent of males die before developing a harem. Harems defended by the … Read more

Ringed Seal

Ringed seals live most of their lives associated with Arctic sea ice. They hunt under the ice for schooling fishes (particularly the Polar Cod) and pelagic invertebrates. In addition to taking advantage of natural cracks or gaps in the ice cover, ringed seals are able to cut and maintain breathing holes, furthering their ability to both hunt … Read more


The narwhal is one of just two species in the “white whales” family, the other being the beluga. As they are closely related and do not have the characteristic tusk of the males, juvenile and female narwhals can be incorrectly identified as belugas. Narwhals typically have more dark coloration, however, than their solid white cousins. Narwhals are restricted … Read more

Juan Fernandez Fur Seal

Its preferred pupping areas include rocky shores and lava flows. This species is not a true seal and is instead closely related to sea lions and other fur seals (together known as the “eared seals”). The Juan Fernandez fur seal is a generalist predator that feeds mostly on shallow reefs near the shore, though it may … Read more

Hawaiian Monk Seal

Hawaiian monk seals are generalist predators known to eat fishes, squids/octopuses, and crustaceans, like crabs and lobsters. They are also one of the few species known to successfully hunt and eat garden eels – elongate, shy eels that live in deep burrows in sand flats near coral reefs – and they have been documented diving to … Read more

Short-beaked Common Dolphin

Short-beaked common dolphins feed on schooling fishes and squids in the open ocean and may follow some fishes as they migrate along currents or oceanic “fronts.” Like their prey, short-beaked common dolphins form large groups (typically composed of hundreds of individuals) for hunting and socializing, and at times, hundreds of these groups come together to form … Read more

Blue Whale

Interestingly, though they are enormous, blue whales are not predatory. They filter feed for tiny krill and are totally harmless to people (other than through accidental collisions). This life history strategy is common among several large animals in the ocean, including the whale shark, the basking shark, and the other great whales. Like all whales, blue whales are … Read more