The Young Pinnipeds / PINNIPEDS

Although pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. They spend most of their lives in the water, but come ashore to mate, give birth, molt or escape from predators, such as sharks and killer whales. Seals mainly live in marine environments but can also be found in freshwater. They feed largely on fish and marine invertebrates; a few, such as the leopard seal, feed on large vertebrates, such as penguins and other seals. Walruses are specialized for feeding on bottom-dwelling mollusks. Male pinnipeds typically mate with more than one female (polygyny), although the degree of polygyny varies with the species. The males of land-breeding species tend to mate with a greater number of females than those of ice breeding species. Male pinniped strategies for reproductive success vary between defending females, defending territories that attract females and performing ritual displays or lek mating. Pups are typically born in the spring and summer months and females bear almost all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively short period of time while others take foraging trips at sea between nursing bouts. Walruses are known to nurse their young while at sea. Seals produce a number of vocalizations, notably the barks of California sea lions, the gong-like calls of walruses and the complex songs of Weddell seals.

In space, no one can hear the seals screaming

All pinnipeds are carnivorous and predatory. As a whole, they mostly feed on fish and cephalopods, followed by crustaceans and bivalves, and then zooplankton and endothermic (“warm-blooded”) prey like sea birds. While most species are generalist and opportunistic feeders, a few are specialists. Examples include the crabeater seal, which primarily eats krill, the ringed seal, which eats mainly crustaceans, the Ross seal and southern elephant seal, which specialize on squid, and the bearded seal and walrus, which feed on clams and other bottom-dwelling invertebrates.

Pinnipeds may hunt solitarily or cooperatively. The former behavior is typical when hunting non-schooling fish, slow-moving or immobile invertebrates or endothermic prey. Solitary foraging species usually exploit coastal waters, bays and rivers. An exception to this is the northern elephant seal, which feeds on fish at great depths in the open ocean. In addition, walruses feed solitarily but are often near other walruses in small or large groups that may surface and dive in unison. When large schools of fish or squid are available, pinnipeds such as certain otariids hunt cooperatively in large groups, locating and herding their prey. Some species, such as California and South American sea lions, may forage with cetaceans and sea birds.

Seals typically consume their prey underwater where it is swallowed whole. Prey that is too large or awkward is taken to the surface to be torn apart. The leopard seal, a prolific predator of penguins, is known to violently swing its prey back and forth until it is dead. The elaborately cusped teeth of filter-feeding species, such as crabeater seals, allow them to remove water before they swallow their planktonic food. The walrus is unique in that it consumes its prey by suction feeding, using its tongue to suck the meat of a bivalve out of the shell. While pinnipeds mostly hunt in the water, South American sea lions are known to chase down penguins on land. Some species may swallow stones or pebbles for reasons not understood. Though they can drink seawater, pinnipeds get most of their fluid intake from the food they eat.

Now they hunt fish in space