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Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphins. Recent molecular studies show the genus contains two species, the Common Bottlenose Dolphin Tursiops truncatus and the Indo Pacific Bottlenose Dolphin Tursiops aduncus, instead of one. They inhabit warm and temperate seas worldwide.

Bottlenose dolphins live in groups typically of 15 members, called pods, but group size varies from single individuals up to more than 1,000. Their diet consists mainly of forage fish. Dolphins often work as a team to harvest fish schools, but they also hunt individually. Dolphins search for prey primarily using echolocation, which is similar to sonar. They emit clicking sounds and listen for the return echo to determine the location and shape of nearby items, including potential prey.

Bottlenose dolphins also use sound for communication, including squeaks and whistles emitted from the blowhole and sounds emitted through body language, such as leaping from the water and slapping their tails on the water surface. There have been numerous studies of their intelligence. Researchers have examined mimicry, use of artificial language, object categorization and self recognition.

Their considerable intelligence has driven interaction with humans. Bottlenose dolphins are popular from aquarium shows and television programs such as Flipper. They have also been trained by militaries to locate sea mines or detect and mark enemy divers. In some areas they cooperate with local fishermen by driving fish into their nets and eating the fish that escape. Some encounters with humans are harmful to the dolphins: people hunt them for food, and dolphins are killed inadvertently as a bycatch of tuna fishing.

The Common dolphin is the name given to up to three species of dolphin making up the genus Delphinus. Prior to the mid 1990s, most taxonomists only recognised one species in this genus, the Common Dolphin Delphinus delphis. Modern cetologists usually recognise two speciesthe Short beaked Common Dolphin, which retains the systematic name Delphinus delphis, and the Long-beaked Common Dolphin Delphinus capensis.

Despite its name the common dolphin is not the dolphin of popular imagination; that distinction belongs to the Bottlenose Dolphin, largely due to its widespread use in marine parks, as well as its appearance in the television series Flipper.

The dolphins have been seen to mix with other cetaceans such as other dolphins in the Yellowfin tuna grounds of the eastern Pacific and also schools of Pilot Whales. An intriguing theory suggests that dolphins 'bow riding' on very large whales was the origin of bow riding on boats. The gestation period is about 11 months and the calving period is between one and three years. Sexual maturation occurs at five years and longevity is twenty to twenty five years. These figures are subject to large variation across different populations.

The Dusky Dolphin is distributed in coastal waters of Chile, Argentina and the Malvinas Islands, Namibia and the west coast of South Africa and all around New Zealand. There may also reside in populations off Tasmania and New South Wales and several small islands in the South Atlantic and Indian Oceans.

An aerial survey off Patagonia in the mid 1990s indicated that there was a local population in excess of 7,000 individuals. Duskies can move over great distances one individual had a confirmed range of 780 nautical miles
1,440 km). However it is not believed that they follow a migratory pattern.

There are few abundance estimates available for any significant portion of the range, 1999. The total number of dusky dolphins in the one area off the Patagonian cost was estimated to be close to 7,252 individuals, 1979 and the number givenin (1999) for the area between Punta Ninfas and Cabo Blanco, Argentina is 6,628. Some subpopulations are thought to have been seriously depleted by human activities (e.g., those off Peru, 1994.).

Dusky dolphins take a wide variety of prey, including southern anchovy near the surface in shallower waters, as well as midwater and benthic prey, such as squid, hake, and lanternfishes. They may also engage in nocturnal feeding, in association with the deep scattering layer. New Zealand dolphins appear to engage in feeding deeper in the water column than do those from Argentine waters.

Commerson's Dolphin Cephalorhynchus commersonii is one of four dolphins in the Cephalorhynchus genus. The species has also the common names Skunk Dolphin and Piebald Dolphin. The dolphin is named for Philibert Commerson, who first described them in 1767 after he sighted them in the Strait of Magellan.

Commerson's Dolphin has a very distinctive patterning. It has a black head, dorsal fin, and fluke, with a white throat and body. The demarcation between the two colours is very clear cut. This stocky creature is one of the smallest of all cetaceans growing to around 1.5 m (5 ft). A mature female caught off of south Patagonia, at 23kg (51 lb) and 1.36 m (4.5 ft), may be the smallest adult cetacean on record.

Its appearance resembles that of a porpoise, but its conspicuous behaviouris typical of a dolphin. The dorsal fin has a long, straight leading edge which ends in a curved tip. The trailing is typically concave but not falcate. The fluke has a notch in the middle. This dolphin has no rostrum. It is not known why their distribution is limited to the southern coast of South America and the Kerguelen Islands.

Sexes are easily distinguished by the different shape of the black blotch on the belly - it is shaped like a teardrop in males but is more rounded in females. Females reach breeding age at six to nine years. Males reach sexual maturity at about the same age. Mating occurs in the spring and summer and calving occurs after a gestation period of 11 months. The oldest known Commerson's Dolphin died at age 18.

Food prepared from fish is also called fish, and is an important human food source. Commercial and subsistence fishers "hunt" them in wild fisheriesor "farm" them in ponds or in cages in the ocean. They are also caught by recreational fishers and raised by fishkeepers, and are exhibited in public aquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies.

The leafy sea dragon, Phycodurus eques, is a marine fish in the family Syngnathidae, which also includes the seahorses. It is the only member of the genus Phycodurus. It is found along the southern and western coasts of Australia. The name is derived from the appearance, with long leaf-like protrusions coming from all over the body. These protrusions are not used for propulsion; they serve only as camouflage. The leafy sea dragon propels itself by means of a pectoral fin on the ridge of its neck and a dorsal fin on its back closer to the tail end. These small fins are almost completely transparent and difficult to see as they undulate minutely to move the creature sedately through the water, completing the illusion of floating seaweed.

Frogfishes, family Antennariidae, are a type of anglerfish in the order Lophiiformes. They are known as anglerfishes in Australia, where 'frogfish' refers to a different type of fish. Frogfishes are found in almost all tropical and subtropical oceans and seas around the world, the primary exception being the Mediterranean Sea.

Frogfish live in the tropical and subtropical regions of the Atlantic and Pacific, as well as in the Indian Ocean and the Red Sea. Their habitat lies for the most part between the 20 degree isotherms, in areas where the surface level water usually has a temperature of 20 C (68 F) or more.

They extend beyond the 20 degree isotherms in the area of the Azores, Madeira, and the Canary Islands, along the Atlantic coast of the USA, on the south coast of Australia and the northern tip of New Zealand, coastal Japan, around Durban, South Africa, and at Baja California.

Clownfish or anemonefish are fishes from the subfamily Amphiprioninae in the family Pomacentridae. About twenty eight species are recognized, one in the genus Premnas, while the remaining are in the genus Amphiprion. In the wild they all form symbiotic mutualisms with sea anemones. Depending on species, clownfish are overall yellow, orange, reddish, or blackish, and many show white bars or patches. The largest reach a length of 18centimetres (7.1in), while the smallest barely reach 10centimetres (3.9in).

Clownfish are native to warmer waters of the Indian and Pacific oceans, including the Great Barrier Reef and the Red Sea. While most species have restricted distributions, others are widespread. They are generally highly host specific, and especially the genera Heteractis and Stichodactyla, and the species Entacmaea quadricolor are frequent partners.

The clownfish feeds on small invertebrates which otherwise potentially could harm the sea anemone, and the fecal matter from the clownfish provides nutrients to the sea anemone. Clownfish are omnivores. Algae accounts for around 20 to 25 percent of its diet in the wild and should also account for its amount of algae diet in captivity as well.

It has also been suggested that the activity of the clownfish results in greater water circulation around the sea anemone. In addition to providing food for the clownfish, the sea anemone also provides safety due to its poison.

The octopus is a cephalopod of the order Octopoda. Octopuses have two eyes and four pairs of arms and like other cephalopods are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms. Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places. Octopuses are highly intelligent, probably the most intelligent of all invertebrates.

The octopus inhabits many diverse regions of the ocean, especially coral reefs. For defense against predators, they hide, flee quickly, expel ink, or use color changing camouflage. An octopus trails its eight arms behind it as it swims. All octopuses are venomous, but only the small blue ringed octopuses are deadly to humans.

In the larger sense, there are around 300 recognized octopus species, which is over one third of the total number of known cephalopod species. The term octopus may also be used to refer only to those creatures in the genus Octopus.

Octopuses have a relatively short life expectancy, and some species live for as little as six months. Larger species, such as the North Pacific Giant Octopus, may live for up to five years under suitable circ*mstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch.

The nine known species range from 0.9 to 6m (3.0 to 20ft) long. All the species have a projection of their face on all sides of the head that gives it a resemblance to a flattened hammer. The hammer like shape of the head was thought to help sharks find food, aiding in close quarters maneuverability and allowing the shark to turn sharply without losing stability. However, it was found that the unusual structure of its vertebrae allowed it to make the turns correctly, more often than its head.

The hammer would also shift and provide lift. It was determined recently that the development of vision led to the hammer like shape. The positioning of the eyes allow for 360 degree vision of the shark. Hammerheads are one of the most negatively buoyant of sharks. Like all sharks, hammerheads have electroreceptory sensory pores called ampullae of Lorenzini. By distributing the receptors over a wider area, hammerheads can sweep for prey more effectively.

These sharks have been able to detect an electrical signal of half a billionth of a volt. The hammer also allows the nostrils to be placed further apart, increasing its ability to detect chemical gradients and localize the source. Hammerheads have disproportionately small mouths and seem to do a lot of bottom hunting. They are also known to form schools during the day, sometimes in groups of over 100. In the evening, like other sharks, they become solitary hunters.

The shark was first described by Peron and Lessueur in 1822 and was given the name Squalus cuvier. Müller and Henle, in 1837 renamed it Galeocerdo tigrinus. The genus, Galeocerdo, is derived from the Greek, galeos which means shark and the Latin cerdus which means the hard hairs of pigs. It is often colloquially called the man eater shark.

The leopard shark Triakis semifasciata is a species of houndshark, family Triakidae, found along the Pacific coast of North America from the U.S. state of Oregon to Mazatlán in Mexico. Typically measuring 1.2–1.5m (3.9–4.9ft) long, this slender-bodied shark is immediately identifiable by the striking pattern of black saddle like markings and large spots over its back, from which it derives its common name.

Large schools of leopard sharks are a common sight in bays and estuaries, swimming over sandy or muddy flats or rock strewn areas near kelp beds and reefs. They are most common near the coast, in water less than 4m (13ft) deep. Active swimming predators, groups of leopard sharks often follow the tide onto intertidal mudflats to forage for food, mainly clams, spoon worms, crabs, shrimp, bony fish, and fish eggs.

Most leopard sharks tend to remain within a particular area rather than undertaking long movements elsewhere, which has led to genetic divergence between populations of sharks living in different regions. This species is ovoviviparous, meaning that the young hatch inside the uterus and are nourished by a yolk sac. From March to June, the female gives birth to as many as 37 young after a gestation period of 10–12 months. This shark is relatively slow growing and takes many years to mature.

Harmless to humans, the leopard shark is caught by commercial and recreational fisheries for food and the aquarium trade. This species is mostly fished in the waters off California where, after a period of population decline in the 1980s, new fishing regulations in the early 1990s reduced harvesting to sustainable levels. The International Union for Conservation of Nature has assessed this species as of Least Concern, while noting that local stocks may easily become overfished because of the shark's slow growth and limited migratory habits.

There are up to five distinct killer whale types distinguished by geographical range, preferred prey items and physical appearance. Some of these may be separate races, subspecies or even species. Killer whales are highly social; some populations are composed of matrilineal family groups which are the most stable of any animal species. The sophisticated social and vocal behaviour of killer whales have been described as manifestations of culture.

The IUCN currently assesses the conservation status of the killer whale as data deficient because of the likelihood that one or more killer whale types could actually be a separate species in need of protection. Some local populations are considered threatened or endangered due to depletion of prey species, habitat loss, pollution by PCBs, historic capture for marine mammal parks, and conflicts with fisheries. In late 2005, the killer whales known as the "southern resident killer whales" were placed on the U.S. Endangered Species list.

Wild killer whales are not considered a threat to humans, although there have been cases of captive killer whales attacking their handlers at marine theme parks. The killer whale features strongly in the mythologies of indigenous cultures. In Western cultures, it has had a reputation for being a fearsome predator, but in recent decades better understanding has led to widespread appreciation of the species.

The humpback whale Megaptera novaeangliae is a baleen whale. One of the larger rorqual species, adults range in length from 12–16 metres (39–52ft) and weigh approximately 36,000kilograms (79,000lb). The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water.

Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time. The purpose of the song is not yet clear, although it appears to have a role in mating. Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 kilometres each year. Humpbacks feed only in summer, in polar waters, and migrate to tropical or sub tropical waters to breed and give birth in the winter.

During the winter, humpbacks fast and live off their fat reserves. The species' diet consists mostly of krill and small fish. Humpbacks have a diverse repertoire of feeding methods, including the bubble net feeding technique. Like other large whales, the humpback was and is a target for the whaling industry. Due to over-hunting, its population fell by an estimated 90% before a whaling moratorium was introduced in 1966.



Stocks have since partially recovered; however, entanglement in fishing gear, collisions with ships, and noise pollution also remain concerns. There are at least 80,000 humpback whales worldwide. Once hunted to the brink of extinction, humpbacks are now sought by whale watchers, particularly off parts of Australia, Canada, and the United States.

The blue whale Balaenoptera musculus is a marine mammal belonging to the suborder of baleen whales called Mysticeti. At up to 32.9metres (108ft) in length and 172metric tons (190short tons) or more in weight, it is the largest animal ever known to have existed.

Long and slender, the blue whale's body can be various shades of bluish grey dorsally and somewhat lighter underneath. There are at least three distinct subspecies: B. m. musculus of the North Atlantic and North Pacific, B. m. intermedia of the Southern Ocean and B. m. brevicauda also known as the pygmy blue whale found in the Indian Ocean and South Pacific Ocean. B. m. indica, found in the Indian Ocean, may be another subspecies

As with other baleen whales, its diet consists almost exclusively of small crustaceans known as krill. Blue whales were abundant in nearly all the oceans until the beginning of the twentieth century. For over 40 years, they were hunted almost to extinction by whalers until protected by the international community in 1966. A 2002 report estimated there were 5,000 to 12,000 blue whales worldwide, located in at least five groups.

More recent research into the Pygmy subspecies suggests this may be an underestimate. Before whaling, the largest population was in the Antarctic, numbering approximately 239,000 range 202,000 to 311,000. There remain only much smaller around 2,000 concentrations in each of the North East Pacific, Antarctic, and Indian Ocean groups. There are two more groups in the North Atlantic, and at least two in the Southern Hemisphere.

Minke whale or lesser rorqual is a name given to two species of marine mammal belonging to a clade within the suborder of baleen whales. The minke whale was given its official designation by Lacepède in 1804, who described a dwarf form of Balænoptera acuto-rostrata.

The minke whales are the second smallest baleen whale only the pygmy right whale is smaller. Upon reaching sexual maturity 6 to 8 years of age, males measure an average of 6.9meters 23ft and females 7.4meters 24ft in length, respectively. Estimates of maximum length vary from 9.1 to 10.7 metres 30 to 35ft for females and 8.8 to 9.8 metres 29 to 32ft for males. Both sexes typically weigh 4 to 5 tonnes at maturity, and the maximum weight may be as much as 14tonnes .

The minke whale is a black gray color. Common minke whales northern hemisphere variety are distinguished from other whales by a white band on each flipper. The body is usually black or dark gray above and white underneath. Minke whales have between 240 and 360 baleen plates on each side of their mouths. Most of the length of the back, including dorsal fin and blowholes, appears at once when the whale surfaces to breathe.

Its diet consists primarily of fish, but can also include crustaceans, such as krill, and cephalopods, such as squid. In hunting, the species can remain submerged up to 18minutes, diving to a depth of 535m (1,755ft). It has several adaptations to facilitate this, including an unusually structured hemoglobin to allow it to function at low oxygen levels, solid bones to reduce barotrauma, and the ability to reduce its metabolism and shut down non essential organ functions.

The Emperor Penguin is perhaps best known for the sequence of journeys adults make each year in order to mate and to feed their offspring. The only penguin species that breeds during the Antarctic winter, it treks 50–120km (31–75mi) over the ice to breeding colonies which may include thousands of individuals. The female lays a single egg, which is incubated by the male while the female returns to the sea to forage; parents subsequently take turns foraging at sea and caring for their chick in the colony.

The lifespan is typically 20years in the wild, although observations suggest that some individuals may live to 50years of age. The Emperor Penguin's diet consists mainly of fish, crustaceans and cephalopods,although its composition varies from population to population. Fish are usually the most important food source, and the Antarctic silverfish makes up the bulk of the bird's diet.

The Royal Penguin Eudyptes schlegeli inhabits the waters surrounding Antarctica. Royals look very much like Macaroni Penguins, but have a white face and chin instead of the Macaronis' black visage. They are about 70cm (28 in) long and weigh about 6kg (13lb). Royal Penguins breed only on Macquarie Island and, like other penguins, spend much of their time at sea, where they are assumed to be pelagic. They are not to be confused with the similar named King Penguin or Emperor Penguin.

There is some controversy over whether Royal Penguins are a sub-species of Macaroni Penguins. Individuals of the two groups have been known to interbreed, though this is a relatively rare occurrence. Indeed, other penguins have been known to form mixed species pairs in the wild.

Royal Penguins nest on beaches or on bare areas on slopes covered with vegetation. Like most seabirds they are colonial, nesting in scrapes on the ground up to a mile inland. The breeding season begins in September with laying starting in October. Two eggs are incubated for 35 days, with each incubation stint lasting up to two weeks.

After brooding the chick for three weeks, both parents forage at sea while the chicks form large creches. The chicks fledge after two months. Young adults usually return to the colony to breed after six years. Royal Penguins feed on krill, fish, and small amounts of squid. They build their nest by making a shallow hole in the sand or in a weeded area. They put plants and stones inside the nest. Most of the time, two eggs are often laid, however, only one survives.

The African Penguin, also known as the Black footed Penguin, is found on the south western coast of Africa, living in colonies on 24 islands between Namibia and Algoa Bay, near Port Elizabeth, South Africa, with the largest colony on Dyer Island, near Kleinbaai. Because of their donkey like braying call they were previously named Jackass Penguins.

Since several species of South American penguins produce the same sound, the African species has been renamed African Penguin, as it is the only penguin species that breeds in Africa. The presence of the penguin gave name to the Penguin Islands. Two colonies were established by penguins in the 1980s on the mainland near Cape Town at Boulders Beach near Simon's Town and Stony Point in Betty's Bay.

Mainland colonies probably only became possible in recent times due to the reduction of predator numbers, although the Betty's Bay colony has been attacked by leopards. The only other mainland colony is in Namibia, but it is not known when this was established. Boulders Beach is a tourist attraction, for the beach, swimming and the penguins.



The penguins will allow people to approach them as close as a meter - three ft. The closest relatives of the African Penguins are the Humboldt Penguin and Magellanic Penguins found in southern South America and the Galápagos Penguin found in the Pacific Ocean near the equator.

The Macaroni Penguin is a species of penguin found from the Subantarctic to the Antarctic Peninsula. One of six species of crested penguin, it is very closely related to the Royal Penguin, and some authorities consider the two to be a single species. It bears a distinctive yellow crest, and the face and upperparts are black and sharply delineated from the white underparts.

Adults weigh on average 5.5kg (12lb) and are 70cm (28in) in length. The male and female are similar in appearance although the male is slightly larger with a relatively larger bill. Like all penguins, it is flightless, with a streamlined body and wings stiffened and flattened into flippers for a marine lifestyle.

The diet consists of a variety of crustaceans, mainly krill, as well as small fish and cephalopods; the species consumes more marine life annually than any other species of seabird. These birds moult once a year, spending about three to four weeks ashore, before returning to the sea. Numbering up to 100,000 individuals, the breeding colonies of the Macaroni Penguin are among the largest and densest of all penguin species.

After spending the summer months breeding, penguins disperse into the oceans for six months; a 2009 study found that Macaroni Penguins from Kerguelen travelled over 10,000km (6,200mi) in the central Indian Ocean. With about 18 million individuals, the Macaroni Penguin is the most numerous penguin species. However, widespread decline in populations have been recorded since the mid 1970s. These factors result in their conservation status being reclassified as vulnerable.

The Little Penguin Eudyptula minor is the smallest species of penguin. The penguin, which is about 43cm (16in) tall, is found on the coastlines of southern Australia and New Zealand, with possible records from Chile.
Apart from Little Penguins, they have several common names. In Australia, they are also referred to as Fairy Penguins because of their tiny size. In New Zealand, they are also called Little Blue Penguins, or just Blue Penguins, owing to their slate-blue plumage, and they are called Kororā in Māori.

The Little Penguin was first described by German naturalist, Johann Reinhold Forster in 1781. There are several subspecies but a precise classification of these is still a matter of dispute. The White-flippered Penguin is sometimes considered a subspecies, sometimes a distinct species, and sometimes a morph. As the Australian and western South Island Little Penguins seem to be a distinct species to which the specific name minor would apply, the White flippered birds indeed belong to a distinct species, although not exactly as originally assumed. Mitochondrial and nuclear DNA evidence suggests the split between Eudyptula and Spheniscus occurred around 25 million years ago, with the ancestors of the White flippered and Little Penguins diverging about 2.7 million years ago.

The Brown Fur Seal Arctocephalus pusillus, also known as the Cape Fur Seal, South African Fur Seal and the Australian Fur Seal is a species of fur seal.The Brown Fur Seal has a large broad head and a pointed snout. Males are brown to dark gray with a darker mane and a light underside. They grow up to 2.2m (7ft) and weigh around 200-360 kg (440-800lb). Females are gray to light brown with a dark underside and light throat.

They grow up to 1.7m (5ft) and weigh on average 120kg (260lbs). Pups are black at birth but turn gray with a pale throat after molting. They are capable of diving to a depth of 600 meters (2000ft).

The Brown Fur Seal is found along the coast of Namibia and along the west coast of South Africa to the Cape of Good Hope and the Cape Province. Its Australian subspecies breeds on nine islands in the Bass Strait between Tasmania and Victoria.

Both subspecies mostly haul out and breed on rocky islands, rock ledges or reefs and pebble or boulder beaches. However South African Fur Seals have large breeding sites on sandy beaches in South Africa, and a non breeding group regularly hauls out on a sandy beach in Cape Fria in northern Namibia.

Sea lions are any of seven species in seven genera of modern pinnipeds including one extinct species ,the Japanese sea lion. Sea lions are characterized by the presence of external ear pinnae ear flaps, long front flippers, the ability to walk on all four flippers on land, and the lack of dense underfur.

Their range extends from the subarctic to tropical waters of the global ocean in both the northern and southern hemispheres with the notable exception of the Atlantic Ocean.

Together with the fur seals, they comprise the Otariidae family, collectively known as eared seals. Until recently, sea lions were grouped under a single subfamily called Otariinae to distinguish them from the fur seals Arcocephalinae, based on the most prominent common feature between all species, namely the lack of the dense underfur characteristic of the latter.

Recent genetic evidence, however, strongly suggests that Callorhinus, the genus of the Northern fur seal is more closely related to some sea lion species than to the other fur seal genus Arctocephalus. Therefore the fur seal and sealion subfamily distinction has been largely eliminated. Nonetheless, all sea lions have certain features in common, in particular their coarse, short fur, greater bulk and larger prey than fur seals.

The Common Seal Phoca vitulina, also known as the Harbor (or Harbour) Seal, is a true seal found along temperate and Arctic marine coastlines of the Northern hemisphere. They are found in coastal waters of the northern Atlantic and Pacific Oceans as well as those of the Baltic and North Seas, making them the most wide ranging of the pinnipeds walruses, eared seals, and true seals.

Common seals are brown, tan, or gray, with distinctive V-shaped nostrils. An adult can attain a length of 1.85 meters (6.1ft) and a mass of 132 kilograms (290lb). Females outlive males (30–35 years versus 20–25 years). Common seals stick to familiar resting spots, generally rocky areas where land predators can't reach them, near a steady supply of fish to eat. Males fight over mates underwater.

Females mate with the strongest males, then bear single pups, which they care for alone. Pups are able to swim and dive within hours of birth, and they grow quickly on their mothers' milk. A fatty tissue called blubber keeps them warm. Their global population is 400,000 to 500,000, and subspecies in certain habitats are threatened. Seal hunting, once a common practice, is now mostly illegal.

While not forming groups as large as some other seals, they are gregarious animals. When not actively feeding, the seals will haul themselves out of the water and onto a preferred resting site. The seals tend to hug the coast, not venturing more than 20 kilometers offshore. Both courtship and mating occurs underwater. The mating system is not known, but thought to be polygamous. Females are thought to give birth once per year, with a gestation period of eleven months.

Elephant seals are large, oceangoing seals in the genus Mirounga. There are two species: the Northern Elephant Seal (M. angustirostris) and the Southern Elephant Seal (M. leonina). Both were hunted to the brink of extinction by the end of the nineteenth century, but numbers have since recovered.

The Northern Elephant Seal, somewhat smaller than its southern relative, ranges over the Pacific coast of the U.S., Canada and Mexico.
The Southern Elephant Seal is found in the southern hemisphere on islands such as South Georgia, Macquarie Island, and on the coasts of New Zealand, South Africa, and Argentina in the Peninsula Valdés, which is the fourth largest elephant seal colony in the world.

Elephant seals take their name from the large proboscis of the adult males bulls which resembles an elephant's trunk. The bull's proboscis is used in producing extraordinarily loud roaring noises, especially during the mating season. More importantly, however, the nose acts as a sort of rebreather, filled with cavities designed to reabsorb moisture from the animals' exhalations.

This is important during the mating season when the male seals rarely leave the beach to feed and therefore must conserve body moisture as they have no incoming source of water. Bulls of both the northern elephant seal and the southern elephant seal reach a length of 16 ft (5 m) and a weight of 6,000 lb (2,700 kg) and are much larger than the cows, which typically measure about 10 ft (3 m) and 2,000 lb (900 kg).

The North American Beaver (Castor canadensis) is the only species of beaver in the Americas, native to North America and introduced to South America. In the United States and Canada, where no other species of beaver occurs, it is usually simply referred to as beaver.

Its other vernacular names, including American beaver and Canadian beaver, distinguish this species from the one other extant beaver, Castor fiber, native to Eurasia. "Canadian beaver" also refers to the subspecies Castor canadensis canadensis.

The beaver's fur consists of long, coarse outer hairs and short, fine inner hairs. The fur has a range of colors but usually is dark brown. Scent glands near the genitals secrete an oily substance known as castoreum, which the beaver uses to waterproof its fur.

The beaver genus Castor is a primarily nocturnal, large, semi aquatic rodent. Castor includes two extant species, Castor canadensis native to North America and Castor fiber Eurasia. Beavers are known for building dams, canals, and lodges homes. They are the secondlargest rodent in the world after the capybara.

Their colonies create one or more dams to provide still, deep water to protect against predators, and to float food and building material. The North American beaver population was once more than 60 million, but as of 1988 was 6–12 million. This population decline is due to extensive hunting for fur, for glands used as medicine and perfume, and because their harvesting of trees and flooding of waterways may interfere with other land uses.

Beavers have webbed hind feet, and a broad, scaly tail. They have poor eyesight, but keen senses of hearing, smell, and touch. A beaver's teeth grow continuously so that they are not worn down by chewing on wood. Their four incisors are composed of hard orange enamel on the front and a softer dentin on the back. The chisel like ends of incisors are maintained by their self-sharpening wear pattern.

Beavers continue to grow throughout life. Adult specimens weighing over 25kg (55lb) are not uncommon. Females are as large as or larger than males of the same age, which is uncommon among mammals. Beavers live up to 24 years of age in the wild.

The European beaver or Eurasian beaver Castor fiber is a species of beaver, which was once widespread in Eurasia, where it has been hunted both for fur and for castoreum, a secretion of its scent gland believed to have medicinal properties. It still occurs as far as China and Mongolia.

The fur colour of European beavers varies geographically. Light, chestnut rust is the dominant colour in Belarus. In Russia, the beavers of the Sozh River basin are predominantly blackish brown, while beavers in the Voronezh Reserve are equally distributed between brown and blackish brown. European beavers on average weigh 18kg, the largest specimen on record having weighed 31.7kg.

Although superficially similar to the North American beaver, there are several important differences. European beavers tend to be bigger, with larger, less rounded heads, longer, narrower muzzles, thinner, shorter, and lighter underfur, narrower, less oval-shaped tails, and have shorter shin bones, making them less capable of bipedal locomotion than the North American species. European beavers have longer nasal bones than their American cousins, with the widest point being at the end of the snout for the former, and in the middle for the latter.

The nasal opening for the European species is triangular, unlike that of the North American race which is square. The foramen magnum is rounded in the European beaver, and triangular in the North American. The anal glands of the European beaver are larger and thin walled with a large internal volume compared to that of the North American breed.

The family Castoridae contains the two living species of beaver and their fossil relatives. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor.

Castorids are medium sized mammals, although large compared with most other rodents. They are semiaquatic, with sleek bodies and webbed hind feet, and are more agile in the water than on land. Their tails are flattened and scaly, adaptations that help them manoeuvre in the water.

Castorids live in small family groups that each occupy a specific territory, based around a lodge and dam constructed from sticks and mud. They are herbivores, feeding on leaves and grasses in the summer, and woody plants such as willow in the winter. They have powerful incisors and the typical rodent -beaver.



The earliest castorids belong to the genus Agnotocastor,known from the late Eocene and Oligocene of North America and Asia (Rybczynski, 2007). Other early castorids included genera such as Steneofiber, from the Oligocene and Miocene of Europe, the earliest member of the subfamily Castorinae, which contains castorids closely related to living beavers (Korth, 2002).

The Oriental Small-clawed Otter Aonyx cinerea, also known as Asian Small clawed Otter, is the smallest otter species in the world, weighing less than 5 kg. It lives in mangrove swamps and freshwater wetlands of Bangladesh, Burma, India, southern China, Taiwan, Laos, Malaysia, Indonesia, the Philippines, Thailand and Vietnam.

This otter is distinctive for its forepaws, as the claws do not extend above the fleshy end pads of its toes and fingers. These attributes give it a high degree of manual dexterity in using its paws to feed on molluscs, crabs and other small aquatic animals.

This species was formerly thought to be the only member of the genus Amblonyx; however, it has recently been confirmed as Aonyx after mitochondrial DNA analysis. Another synonym for the Oriental small clawed otter is Aonyx cinereus.

The European Otter Lutra lutra, also known as the Eurasian otter, Eurasian river otter, common otter and Old World otter, is a European and Asian member of the Lutrinae or otter subfamily, and is typical of freshwater otters. It differs from the North American river otter by its shorter neck, broader visage, the greater space between the ears and its longer tail.

The European Otter is the most widely distributed otter species, its range including parts of Asia and Africa as well as being spread across Europe. It is believed to be currently extinct in Liechtenstein, and Switzerland, It is proven to be extinct in the Netherlands. They are now very common in Latvia, along the coast of Norway and in Northern Britain, especially Shetland where 12% of the UK breeding population exist. In Italy, they can be found in the Calore river area.

The European Otter's diet mainly consists of fish but can also include birds, insects, frogs, crustaceans and sometimes small mammals, including young beavers. In general this opportunism means they may inhabit any unpolluted body of freshwater, including lakes, streams, rivers, and ponds, as long as there is good supply of food.

European Otters may also live along the coast, in salt water, but require regular access to freshwater to clean their fur. When living in the sea individuals of this species are sometimes referred to as "sea otters", but they should not be confused with the true sea otter, a North American species much more strongly adapted to a marine existence.

The sea otter Enhydra lutris is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between 14 and 45kg (30 to 100lb), making them the heaviest members of the weasel family, but among the smallest marine mammals. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Although it can walk on land, the sea otter lives mostly in the ocean.

The sea otter inhabits nearshore environments where it dives to the sea floor to forage. It preys mostly upon marine invertebrates such as sea urchins, various molluscs and crustaceans, and some species of fish. Its foraging and eating habits are noteworthy in several respects. First, its use of rocks to dislodge prey and to open shells makes it one of the few mammal species to use tools. In most of its range, it is a keystone species, controlling sea urchin populations which would otherwise inflict extensive damage to kelp forest ecosystems.

Its diet includes prey species that are also valued by humans as food, leading to conflicts between sea otters and fisheries. Sea otters, whose numbers were once estimated at 150,000–300,000, were hunted extensively for their fur between 1741 and 1911, and the world population fell to 1,000–2,000 individuals in a fraction of their historic range. A subsequent international ban on hunting, conservation efforts, and reintroduction programs into previously populated areas have contributed to numbers rebounding, and the species now occupies about two-thirds of its former range.



The recovery of the sea otter is considered an important success in marine conservation, although populations in the Aleutian Islands and California have recently declined or have plateaued at depressed levels. For these reasons as well as its particular vulnerability to oil spills the sea otter remains classified as an endangered species.

The Giant Otter Pteronura brasiliensis is a South American carnivorous mammal. It is the longest member of the Mustelidae, or weasel family, a globally successful group of predators. Unusually for a mustelid, the Giant Otter is a social species, with family groups typically supporting three to eight members. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial and aggression has been observed between groups. The Giant Otter is diurnal, being active exclusively during daylight hours.

It is the noisiest otter species and distinct vocalizations have been documented that indicate alarm, aggressiveness, and reassurance. The Giant Otter ranges across north central South America. Its distribution has been greatly reduced and is now discontinuous. Decades of poaching for its velvety pelt, peaking in the 1950s and 1960s, hugely diminished population numbers. The species was listed as endangered in 1999 and population estimates are typically below 5,000 in the wild.

The Guianas are the last real stronghold for the species. It is the most endangered mammal in the neo tropics. Habitat degradation and loss is the greatest current threat. The Giant Otter is also rare in captivity: as of 2003, only 60 animals were held. The Giant Otter shows a variety of adaptations suitable to an amphibious lifestyle, including exceptionally dense fur, a wing like tail, and webbed feet. The species prefers freshwater rivers and streams, which are usually seasonally flooded, and may also take to freshwater lakes and springs.

It constructs extensive campsites close to feeding areas, clearing large amounts of vegetation. The Giant Otter largely subsists on a diet of fish, particularly characins and catfish, and may also eat crabs. It has no serious natural predators other than humans, although it must compete with other species, including the Neotropical Otter and caiman species, for food resources.

The walrus Odobenus rosmarus is a large flippered marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and sub Arctic seas of the Northern Hemisphere. The walrus is the only living species in the Odobenidae family and Odobenus genus. It is subdivided into three subspecies,the Atlantic Walrus O. rosmarus rosmarus found in the Atlantic Ocean, the Pacific Walrus O. rosmarus divergens found in the Pacific Ocean, and O. rosmarus laptevi, found in the Laptev Sea.

The walrus is immediately recognized by its prominent tusks, whiskers and great bulk. Adult Pacific males can weigh up to 2,000kilograms (4,400lb) and, among pinnipeds, are exceeded in size only by the two species of elephant seals. It resides primarily in shallow oceanic shelf habitat, spending a significant proportion of its life on sea ice in pursuit of its preferred diet of benthic bivalve mollusks. It is a relatively long lived, social animal and is considered a keystone species in Arctic marine ecosystems.

The walrus has played a prominent role in the cultures of many indigenous Arctic peoples, who have hunted the walrus for its meat, fat, skin, tusks and bone. In the 19th and early 20th centuries, the walrus was the object of heavy commercial exploitation for blubber and ivory and its numbers declined rapidly. Its global population has since rebounded, though the Atlantic and Laptev populations remain fragmented and at historically depressed levels.

The origin of walrus has variously been attributed to combinations of the Dutch words walvis ("whale") and ros ("horse") or wal ("shore") and reus ("giant"). However, the most likely origin of the word is the Old Norse hrossvalr, meaning "horse-whale", which was passed in a juxtaposed form to Dutch and the North-German dialects as walros and Walross.

Walruses live to about 20-30 years old in the wild. The males reach sexual maturity as early as 7 years, but do not typically mate until fully developed around 15 years of age. They rut from January through April, decreasing their food intake dramatically. The females begin ovulating as soon as 4 to 6 years old. The females are polyestrous, coming into heat in late summer and also around February, yet the males are fertile only around February; the potential fertility of this second period is unknown. Breeding occurs from January to March, peaking in February.