Marine Mammals

Belugas are extremely sociable mammals that live, hunt and migrate together in pods, ranging from a few individuals to hundreds of whales. Their bulbous forehead, called a 'melon”, is flexible and capable of changing shape. This allows them to make different facial expressions. Belugas can produce a series of chirps, clicks, whistles and squeals, which give the beluga its other name, 'the canary of the sea.' They may sound like music or even nonsense to us, but to fellow belugas they convey important information. Many populations of belugas migrate as the sea ice changes in the Arctic. They move south in the fall as the ice forms and then return to feed again in the spring, as the ice breaks up. They can also be found near river mouths, and sometimes even venture up river. Belugas feed on a variety of fish species, such as salmon and herring, as well as shrimp, crabs and mollusks.

Dolphin, any of the toothed whales belonging to the mammal family Delphinidae (oceanic dolphins) as well as the families Platanistidae and Iniidae, the two that contain the river dolphins. Of the nearly 40 species of dolphins in the Delphinidae, 6 are commonly called whales, including the killer whale and the pilot whales. The name dolphin is also applied to members of the fish genus Coryphaena (family Coryphaenidae). Most dolphins are small, measuring less than 3 metres (10 feet) in length, and have spindle-shaped bodies, beaklike snouts (rostrums), and simple needlelike teeth. Some of these cetaceans are occasionally called porpoises, but scientists prefer to use this term as the common name for the six species in the family Phocoenidae, all of which differ from dolphins in having blunt snouts and spadelike teeth. Dolphins are popularly noted for their grace, intelligence, playfulness, and friendliness to humans. The most widely recognized species are the common and bottlenose dolphins (Delphinus delphis and Tursiops truncatus, respectively). The bottlenose, characterized by a “built-in smile” formed by the curvature of its mouth, has become a familiar performer in oceanariums. It has also become the subject of scientific studies because of its intelligence and ability to communicate by using a range of sounds and ultrasonic pulses. It adapts to captivity better than the common dolphin, which is timid.

Most seals are at home in frigid waters, but the Hawaiian monk seal is a rare tropical exception. Hawaiian monk seals live in the remote Northwestern Hawaiian Islands. These small islands and atolls are either uninhabited or little-used by humans. They are also surrounded with teeming coral reefs, which serve as great foraging grounds for skilled seals to swim and dive for fish, spiny lobsters, octopuses, and eels. Monk seals spend most of their time at sea, but they come ashore to rest on beaches and use fringe vegetation as shelter from storms.

Marine Otters are the smallest species of otter in the genus Lontra. They have a body length between 50 and 79 cms (20 - 31 inches), a tail length between 30 and 36 cms (12 - 14 inches) and they weigh between 3 and 5 kgs (6.6 - 11 lbs). Marine Otters are found exclusively in marine habitats along the Pacific coast of South America, from northern Peru, along the coast of Chile, to the southern tip of South America. Marine Otters breed once a year and after a gestation period of 60 - 65 days, 2 - 4 youngsters are born. The youngsters remain with their parents until they reach independence at 10 months old.

The narwhal is the unicorn of the sea, a pale-colored porpoise found in Arctic coastal waters and rivers. These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, spiral tusk up to 10 feet long. The ivory tusk tooth grows right through the narwhal's upper lip. Scientists are not certain of the tusk's purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male's.

The killer whale, also known as orca, is one of the top marine predators. It is the largest member of the Delphinidae family, or oceanic dolphins. Members of this family include all dolphin species, as well as other larger species such as the long-finned pilot whales and short-finned pilot whales, whose common names also contain 'whale' instead of 'dolphin.' Killer whales are mostly black on top with white undersides and white patches near the eyes. They also have a gray or white saddle patch behind the dorsal fin. These markings vary widely between individuals and populations. Adult males develop disproportionately larger pectoral flippers, dorsal fins, tail flukes, and girths than females.

California sea lions are “eared seals” native to the West Coast of North America. They live in coastal waters and on beaches, docks, buoys, and jetties. They are easily trained and intelligent and are commonly seen in zoos and aquariums. California sea lions are playful, intelligent, and very vocal (sounding like barking dogs). Adult females and juveniles are slender-bodied and are blonde to tan in color. Adult males are generally larger than females and are mostly dark brown to black in color. Pups are dark brown at birth and weigh about 16 pounds. When pups are 4 to 5 months old, they molt their dark brown coats for light brown or silver coats. California sea lions have broad front flippers and long, narrow snouts. Subadult and adult males have pronounced forehead crests crowned with tufts of blonde or lighter hair. California sea lions have visible ear flaps, and three to five claws on their hind flippers.

Sperm whales are easily recognized by their massive heads and prominent rounded foreheads. They have the largest brain of any creature known to have lived on Earth. Their heads also hold large quantities of a substance called spermaceti. Whalers once believed that the oily fluid was sperm, but scientists still do not understand the function of spermaceti. One common theory is that the fluid—which hardens to wax when cold—helps the whale alter its buoyancy so it can dive deep and rise again. Sperm whales are known to dive as deep as 3,280 feet in search of squid to eat. These giant mammals must hold their breath for up to 90 minutes on such dives. These toothed whales eat thousands of pounds of fish and squid—about one ton per day. Sperm whales are often spotted in groups (called pods) of some 15 to 20 animals. Pods include females and their young, while males may roam solo or move from group to group. Females and calves remain in tropical or subtropical waters all year long, and apparently practice communal childcare. Males migrate to higher latitudes, alone or in groups, and head back towards the equator to breed. Driven by their tale fluke, approximately 16 feet from tip to tip, they can cruise the oceans at around 23 miles per hour. These popular leviathans are vocal and emit a series of “clangs” that may be used for communication or for echolocation. Animals that use echolocation emit sounds that travel underwater until they encounter objects, then bounce back to their senders—revealing the location, size, and shape of their target.

Subantarctic fur seals are uniquely colored amongst otariids; their dark brown or gray dorsal surface contrasts with a pale ventral surface. They are strongly sexually dimorphic with adult males some three times heavier than adult females. Subantarctic fur seals breed on seven island groups in the Southern Ocean, north of the Antarctic Polar Front. Some 99% of pup production takes place at Gough Island, the Prince Edward Islands, and Amsterdam Island. Adults haul out in the austral summer to breed in polygynous aggregations. Following this, adult females undertake regular foraging trips typically of several hundred kilometers each until their pups are weaned at 10 months of age. Prey is primarily myctophid fish and cephalopods. Although this species was reduced to low numbers by commercial sealing by the early 20th century, the population has since grown to some 400,000 and its conservation designation is Least Concern.

The mustached and long-tusked walrus is most often found near the Arctic Circle, lying on the ice with hundreds of companions. These marine mammals are extremely sociable, prone to loudly bellowing and snorting at one another, but are aggressive during mating season. With wrinkled brown and pink hides, walruses are distinguished by their long white tusks, grizzly whiskers, flat flipper, and bodies full of blubber. The two subspecies of walrus are divided geographically. Atlantic walruses inhabit coastal areas from northeastern Canada to Greenland, while Pacific walruses inhabit the northern seas off Russia and Alaska, migrating seasonally from their southern range in the Bering Sea—where they are found on the pack ice in winter—to the Chukchi Sea. Female Pacific walruses give birth to calves during the spring migration north.