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Marine Mammal
Marine mammals are mammals that rely on marine (saltwater) ecosystems for their existence. They include animals such as cetaceans ( whales, dolphins and porpoises), pinnipeds (seals, sea lions and walruses), sirenians ( manatees and dugongs), sea otters and polar bears. They are an informal group, unified only by their reliance on marine environments for feeding and survival. Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Pinnipeds are semiaquatic; they spend the majority of their time in the water but need to return to land for important activities such as mating, breeding and molting. Sea otters tend to live in kelp forests and estuaries. In contrast, the polar bear is mostly terrestrial and only go into the water on occasions of necessity, and are thus much less adapted to aquatic living. The diets of marine mammals vary considerably as we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sirenian
The Sirenia (), commonly referred to as sea-cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise two distinct families: Dugongidae (the dugong and the now extinct Steller's sea cow) and Trichechidae (manatees, namely the Amazonian manatee, West Indian manatee, and West African manatee) with a total of four species. The Protosirenidae (Eocene sirenians) and Prorastomidae (terrestrial sirenians) families are extinct. Sirenians are classified in the clade Paenungulata, alongside the elephants and the hyraxes, and evolved in the Eocene 50 million years ago (mya). The Dugongidae diverged from the Trichechidae in the late Eocene or early Oligocene (30–35 mya). Sirenians grow to between in length and in weight. The historic Steller's sea cow was the largest known sirenian to have lived, and could reach lengths of and weights of . Sirenians have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humpback Whale Underwater Shot
Humpback may refer to: * Humpback whale * Humpback dolphin * Humpback salmon * Humpback bridge * Humpback, a common name for the fish ''Chanodichthys dabryi'' * Humpback, a variant of hunchback Kyphosis is an abnormally excessive convex curvature of the spine as it occurs in the thoracic and sacral regions. Abnormal inward concave ''lordotic'' curving of the cervical and lumbar regions of the spine is called lordosis. It can result fr ... {{disambiguation, fish Animal common name disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mating
In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. ''Copulation'' is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. Mating may also lead to external fertilization, as seen in amphibians, fishes and plants. For most species, mating is between two individuals of opposite sexes. However, for some hermaphroditic species, copulation is not required because the parent organism is capable of self-fertilization (autogamy); for example, banana slugs. The term ''mating'' is also applied to related processes in bacteria, archaea and viruses. Mating in these cases involves the pairing of individuals, accompanied by the pairing of their homologous chromosomes and then exchange of genomic information leading to formation of recombinant progeny (see mating systems). Animals For animals, mating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bycatch
Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juveniles of the target species. The term "bycatch" is also sometimes used for untargeted catch in other forms of animal harvesting or collecting. Non- marine species (freshwater fish not saltwater fish) that are caught (either intentionally or unintentionally) but regarded as generally "undesirable" are referred to as "rough fish" (mainly US) and " coarse fish" (mainly UK). In 1997, the Organisation for Economic Co-operation and Development (OECD) defined bycatch as "total fishing mortality, excluding that accounted directly by the retained catch of target species". Bycatch contributes to fishery decline and is a mechanism of overfishing for unintentional catch. The average annual bycatch rate of pinnipeds and cetaceans in the US from 199 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Atlantic Right Whale
The North Atlantic right whale (''Eubalaena glacialis'') is a baleen whale, one of three right whale species belonging to the genus ''Eubalaena'', all of which were formerly classified as a single species. Because of their docile nature, their slow surface-skimming feeding behaviors, their tendencies to stay close to the coast, and their high blubber content (which makes them float when they are killed, and which produced high yields of whale oil), right whales were once a preferred target for whalers. At present, they are among the most endangered whales in the world, and they are protected under the U.S. Endangered Species Act and Marine Mammal Protection Act and Canada's Species at Risk Act. There are fewer than 370 individuals in existence in the western North Atlantic Ocean—they migrate between feeding grounds in the Labrador Sea and their winter calving areas off Georgia and Florida, an ocean area with heavy shipping traffic. In the eastern North Atlantic, on the other ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Elephant Seal
The northern elephant seal (''Mirounga angustirostris'') is one of two species of elephant seal (the other is the southern elephant seal). It is a member of the family (biology), family Phocidae (true seal (mammal), seals). Elephant seals derive their name from their great size and from the male's large proboscis, which is used in making extraordinarily loud roaring noises, especially during the mating competition. Sexual dimorphism in size is great. Correspondingly, the mating system is highly polygynous; a successful male is able to impregnate up to 50 females in one season. Description The huge male northern elephant seal typically weighs and measures , although some males can weigh up to . Females are much smaller and can range from in weight, or roughly a third of the male's bulk, and measure from . The bull southern elephant seals are, on average, larger than those in the northern species, but the females in both are around the same size, indicating the even higher level ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gray Whale
The gray whale (''Eschrichtius robustus''), also known as the grey whale,Britannica Micro.: v. IV, p. 693. gray back whale, Pacific gray whale, Korean gray whale, or California gray whale, is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of , a weight of up to and lives between 55 and 70 years, although one female was estimated to be 75–80 years of age. The common name of the whale comes from the gray patches and white mottling on its dark skin. Gray whales were once called devil fish because of their fighting behavior when hunted. The gray whale is the sole living species in the genus ''Eschrichtius''. It was formerly thought to be the sole living genus in the family (biology), family Eschrichtiidae, but more recent evidence classifies members of that family in the family Rorqual, Balaenopteridae. This mammal is descended from filter-feeding whales that appeared during the Neogene. The gray whale is distributed in an eastern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caribbean Monk Seal
The Caribbean monk seal (''Neomonachus tropicalis''), also known as the West Indian seal or sea wolf, was a species of seal native to the Caribbean which is now believed to be extinct. The main predators of Caribbean monk seals were sharks and humans. Overhunting of the seals for oil and overfishing of their food sources are the established reasons for the seals' extinction. The last confirmed sighting of the Caribbean monk seal was in 1952 at Serranilla Bank, between Jamaica and Nicaragua. In 2008, the species was officially declared extinct by the United States, after an exhaustive five-year search. This analysis was conducted by the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration. Caribbean monk seals were closely related to Hawaiian monk seals, which live around the Hawaiian Islands and are now endangered, and Mediterranean monk seals, another endangered species. Description Caribbean monk seals had a relatively large, long, robu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Sea Lion
The Japanese sea lion (''Zalophus japonicus'') ( ja, ニホンアシカ, translit=Nihon ashika, Korean:강치, 바다사자) was an aquatic mammal that became extinct in the 1970s. It was considered to be a subspecies of the related California sea lion (''Z. californianus'') until 2003. They inhabited the Sea of Japan, especially around the coastal areas of the Japanese Archipelago and the Korean Peninsula. They generally bred on sandy beaches which were open and flat, but sometimes in rocky areas. They were hunted commercially in the 1900s, leading to their extinction. Taxonomy Prior to 2003, it was considered to be a subspecies of California sea lion as ''Zalophus californianus japonicus''. However, it was subsequently reclassified as a separate species. DNA analysis in 2007 estimated that the divergence point between the two sea lions took place around 2 million years ago (mya) in the early Pleistocene. Several taxidermied specimens can be found in Japan and in the National M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Mink
The sea mink (''Neogale macrodon'') is a recently extinct species of mink that lived on the eastern coast of North America around the Gulf of Maine on the New England seaboard. It was most closely related to the American mink (''Neogale vison''), with continuing debate about whether or not the sea mink should be considered a subspecies of the American mink (as ''Neogale vison macrodon'') or a species of its own. The main justification for a separate species designation is the size difference between the two minks, but other distinctions have been made, such as its redder fur. The only known remains are bone fragments unearthed in Native American shell middens. Its actual size is speculative, based largely on tooth remains. The sea mink was first described in 1903, after its extinction; information regarding its external appearance and habits stem from speculation and from accounts made by fur traders and Native Americans. It may have exhibited behavior similar to the American m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steller's Sea Cow
Steller's sea cow (''Hydrodamalis gigas'') is an extinct sirenian described by Georg Wilhelm Steller in 1741. At that time, it was found only around the Commander Islands in the Bering Sea between Alaska and Russia; its range extended across the North Pacific during the Pleistocene epoch, and likely contracted to such an extreme degree due to the glacial cycle. It is possible indigenous populations interacted with the animal before Europeans. Steller first encountered it on Vitus Bering's Great Northern Expedition when the crew became shipwrecked on Bering Island. Much of what is known about its behavior comes from Steller's observations on the island, documented in his posthumous publication ''On the Beasts of the Sea''. Within 27 years of its discovery by Europeans, the slow-moving and easily-caught mammal was hunted into extinction for its meat, fat, and hide. Some 18th-century adults would have reached weights of and lengths up to . It was a member of the family Dugongida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
