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Dolphin

Dolphin

See article below. Dolphins are aquatic mammals related to whales and porpoises. The name is from Ancient Greek delphis meaning "with a womb", viz. "a 'fish' with a womb". The word is used in a few different ways. It can mean: #Any member of the family Delphinidae (oceanic dolphins), #Any member of the families Delphinidae and Platanistoidea (oceanic and river dolphins), #Any member of the suborder Odontoceti (toothed whales; these include the above families and some others), #Used casually as a synonym for Bottlenose Dolphin, the most common and familiar species of dolphin. In this article, the second definition is used. Porpoises (suborder Odontoceti, family Phocoenidae) are thus not dolphins in our sense. Orcas and some related species belong to the Delphinidae family and therefore qualify as dolphins, even though they are called whales in common language. There are almost 40 species of dolphin in 17 genera. They vary in size from 1.2 m (4 ft) and 40 kg (88 lb) (Maui's Dolphin), up to 9.5 m (30 ft) and 10 tonnes (the Orca). Most species weigh about 50 to 200 kg (110 to 440 lb). They are found worldwide, mostly in the shallower seas of the continental shelves, and all are carnivores, mostly eating fish and squid. The family Delphinidae is the largest in the Cetacea, and relatively recent: dolphins evolved about 10 million years ago, during the Miocene.

Taxonomy


- Suborder Odontoceti, toothed whales
  - Family Delphinidae, oceanic Dolphins
    - Genus Delphinus
      - Long-Beaked Common Dolphin, Delphinus capensis
      - Short-Beaked Common Dolphin, Delphinus delphis
    - Genus Tursiops
      - Bottlenose Dolphin, Tursiops truncatus
    - Genus Lissodelphis
      - Northern Rightwhale Dolphin, Lissodelphis borealis
      - Southern Rightwhale Dolphin, Lissiodelphis peronii
    - Genus Sotalia
      - Tucuxi, Sotalia fluviatilis
    - Genus Sousa
      - Indo-Pacific Hump-backed Dolphin, Sousa chinensis
      -
- Chinese White Dolphin, the Chinese variant
      - Atlantic Humpbacked Dolphin, Sousa teuszii
    - Genus Stenella
      - Atlantic Spotted Dolphin, Stenella frontalis
      - Clymene Dolphin, Stenella clymene
      - Pantropical Spotted Dolphin, Stenella attenuata
      - Spinner Dolphin, Stenella longirostris
      - Striped Dolphin, Stenella coeruleoalba
    - Genus Steno
      - Rough-Toothed Dolphin, Steno bredanensis
    - Genus Cephalorynchus
      - Chilean Dolphin, Cephalorhynchus eutropia
      - Commerson's Dolphin, Cephalorhynchus commersonii
      - Heaviside's Dolphin, Cephalorhynchus heavisidii
      - Hector's Dolphin, Cephalorhynchus hectori
    - Genus Grampus
      - Risso's Dolphin, Grampus griseus
    - Genus Lagenodelphis
      - Fraser's Dolphin, Lagenodelphis hosei
    - Genus Lagenorhyncus
      - Atlantic White-Sided Dolphin, Lagenorhynchus acutus
      - Dusky Dolphin, Lagenorhynchus obscurus
      - Hourglass Dolphin, Lagenorhynchus cruciger
      - Pacific White-Sided Dolphin, Lagenorhynchus obliquidens
      - Peale's Dolphin, Lagenorhynchus australis
      - White-Beaked Dolphin, Lagenorhynchus albirostris
    - Genus Orcaella
      - Australian Snubfin Dolphin, Orcaella heinsohni
      - Irrawaddy Dolphin, Orcaella brevirostris
    - Genus Peponocephalia
      - Melon-headed Whale, Peponocephalia electra
    - Genus Orcinus
      - Killer Whale, Orcinus orca
    - Genus Feresa
      - Pygmy Killer Whale, Feresa attenuata
    - Genus Pseudorca
      - False Killer Whale, Pseudorca crassidens
    - Genus Globicephala
      - Long-finned Pilot Whale, Globicephala melas
      - Short-finned Pilot Whale, Globicephala macrorhynchus
  - Family Platanistoidea, River Dolphins
    - Genus Inia
      - Boto (Amazon River Dolphin), Inia geoffrensis
    - Genus Lipotes
      - Chinese River Dolphin (Baiji), Lipotes vexillife
    - Genus Platanista
      - Ganges River Dolphin, Platanista gangetica
      - Indus River Dolphin, Platanista minor
    - Genus Pontoporia
      - La Plata Dolphin (Franciscana), Pontoporia blainvillei Six animals in the family Delphinidae are commonly called "whales" but are strictly speaking dolphins. They are sometimes called "blackfish":
- Melon-headed Whale, Peponocephalia electra
- Killer Whale, Orcinus orca
- Pygmy Killer Whale, Feresa attenuata
- False Killer Whale, Psudoorca crassidens
- Long-finned Pilot Whale, Globicephala melas
- Short-finned Pilot Whale, Globicephala macrorhynchus

Hybrid Dolphins

In 1933, three strange dolphins were beached off the Irish coast; these appeared to be hybrids between Risso's Dolphin and the Bottlenose Dolphin. This mating has since been repeated in captivity and a hybrid calf was born. In captivity, a Bottlenose Dolphin and a Rough-Toothed Dolphin produced hybrid offspring. In the wild, Spinner Dolphins have sometimes hybridised with Spotted Dolphins and Bottlenose Dolphins. In the wild, bands of males of one dolphin species have been observed to mate with lone female Spinners. Blue Whales, Fin Whales and Humpback Whales all hybridize in the wild. Dall's Porpoises and Harbour Porpoises have hybridized in the wild. There has also been a reported hybrid between a beluga and a narwhal. See also wolphin.

Evolution and anatomy of dolphins

Dolphins, along with whales and porpoises, are descendants of land-living mammals, most likely of the Artiodactyl order. Modern dolphin skeletons have two small rod shaped pelvic bones thought to be left-over hind legs. They entered the water roughly 50 million years ago. See evolution of cetaceans for the details. Dolphins have a fusiform body, adapted for fast swimming. The head contains the melon, a round organ used for echolocation. In many species, the jaws are elongated, forming a distinct beak; for some species like the Bottlenose, there is a curved mouth that looks like a fixed smile. Teeth can be very numerous (up to 250) in several species. The dolphin brain is large and has a highly structured cortex, which often is referred to in discussions about their high intelligence. The basic coloration patterns are shades of gray with a light underside and a distinct dark cape on the back. It is often combined with lines and patches of different hue and contrast. See individual species articles for details.

Dolphin behavior

dolphin brain Dolphins are widely believed to be amongst the most intelligent of all animals. A typical statement would be that dolphins are roughly as intelligent as a two-year-old human. However, experts in comparative psychology or animal cognition would be reluctant to make any such estimate, as quantitative comparisons of intelligence between species are notoriously difficult to make in principle. Straightforward comparisons of species' relative intelligence are complicated by differences in sensory apparatus, response modes, and nature of cognition; furthermore, the difficulty and expense of doing experimental work with a large marine animal mean that even such tests as can meaningfully be done have still not been done, or have been carried out with inadequate sample size and methodology. See the Dolphin intelligence article for more details. Dolphins often leap above the water surface, sometimes performing acrobatic figures (e.g. the spinner dolphin). This and other behavior is interpreted as playing. They are capable of diving up to 260 m deep and 15 min long, but rarely stay underwater longer than few minutes. Frequently dolphins will accompany boats, riding the bow waves. They are also famous for their willingness to occasionally approach humans and playfully interact with them in the water. In return, in some cultures like in Ancient Greece they were treated with welcome; a ship spotting dolphins riding in their wake was considered a good omen for a smooth voyage. There have been reports of dolphins protecting swimmers against sharks by swimming circles around the swimmers. Dolphins are social animals, living in pods (also called "schools") of up to a dozen animals. In places with a high abundance of food, schools can join temporarily, forming an aggregation called a superpod; such groupings may exceed 1000 dolphins. The individuals communicate using a variety of clicks, whistles and other vocalizations. They also use ultrasonic sounds for echolocation. echolocation Membership in schools is not rigid; interchange is common. However, the animals can establish strong bonds between each other. This leads to them staying with injured or ill fellows for support. Because of their high capacity for learning, humans have employed dolphins for any number of purposes. Dolphins trained to perform in front of an audience have become a favorite attraction in dolphinaria, for example SeaWorld. Dolphin/Human interaction is also employed in a curative sense at places where dolphins work with autistic or otherwise disabled children. The military has employed dolphins for various purposes from finding mines to rescuing lost or trapped persons. Such military dolphins, however, drew scrutiny during the Vietnam War when rumors circulated that dolphins were being trained to kill Vietnamese Skin Divers. In May 2005, researchers in Australia discovered a cultural aspect of dolphin behaviour: Some dolphins (Tursiops aduncus) teach their offspring to use a tool. The animals break off sponges and put them onto their mouths thus protecting the delicate body part during their hunt for fish on the seabed. Other than with primate simians, the knowledge to use a tool is mostly handed over only from mothers to daughters. The technology to use sponges as mouth protection is not genetically inherited but a taught cultural behaviour. Dolphins do not have acute eyesight nor do they appear to have a good sense of smell, although their sense of hearing is far above our own. Compare also: whale behavior

Feeding

Dolphins are predators, chasing their prey at high speed. The dentition is adapted to the animals they hunt: Species with long beaks and many teeth forage on fish, whereas short beaks and lesser tooth count are linked to catching squid. Some dolphins may take crustaceans. Usually, the prey is swallowed whole. The bigger species, especially the orca, are capable of eating marine mammals, even large whales. There are no known reports of cannibalism amongst dolphins. Individual species may employ a number of methods of hunting:
- Herding - where a superpod will control a school of fish while individual members take turns plowing through the herd, feeding.
- Corralling - where fish are chased to shallow water where they are more easily captured.
- Fish Wacking - where the dolphin uses its fluke to strike the fish, stunning it and sometimes sending it clear out of the water.
- Stunning - using the echolocation melon, very loud clicks are directed at prey, stunning them.
- Foraging - A recent study reported that wild bottlenose dolphins (Tursiops sp.) in Western Australia use sponges to forage in the sea bed for food.[http://www.pnas.org/cgi/content/abstract/0500232102v1]

Dolphin lore


- The popular television show Flipper, created by Ivan Tors, portrayed a dolphin in a friendly relationship with two boys, Sandy and Bud; a kind of sea going Lassie, Flipper understood English unusually well and was a marked hero: "Go tell Dad we're in trouble, Flipper! Hurry!" The show's theme song contains the lyric no one you see / is smarter than he.
- In The Hitchhiker's Guide to the Galaxy, dolphins are very intelligent creatures who tried in vain to warn humans of the impending destruction of Earth. However, their behavior was misinterpreted as playful acrobatics. Their story is told in So Long, and Thanks for All the Fish.
- After study at the Dolphins Plus research center in Key Largo, Florida, fantasy author Ken Grimwood wrote dolphins into his 1995 novel Into the Deep, including entire chapters written from the viewpoint of his dolphin characters.
- Ecco The Dolphin stars in a series of games for the Sega Genesis/Mega Drive, Game Gear, Sega Dreamcast and Playstation 2.
- A book called 'The Music of Dolphins' was written by Karen Hesse, about a girl who had lived with dolphins since the age of four.
- An American National Football League (NFL) team is named the Miami Dolphins. Their logo depicts an aqua-colored bottlenose dolphin wearing an American football helmet and jumping in front of a coral-colored sunburst.
- The Mystery Science Theater 3000 episode Devil Fish, features Mike and the 'Bots mocking dolphins. While doing so, the SOL gets blasted by a ship that turns out to be piloted by dolphins. Mike and the 'Bots then quickly apoligize.

See also


- Dolphin (mythology)
- List of dolphin species
- Wolphin

See also


- John Lilly – Dolphin intelligence researcher
- Cetacean intelligence – Article about dolphin intelligence

External links


- [http://news.bbc.co.uk/2/hi/asia-pacific/4034383.stm Dolphins help lifeguards from sharks]
- [http://www.cetacea.org/ Cetacea.org site]
- [http://www.robins-island.org/ Facts and Information on Dolphins]
- [http://www.hickerphoto.com/dolphin-pictures-cat.htm Dolphin Pictures]
- [http://www.robertosozzani.it/Delfini/cont.html Red Sea Spinner Dolphin - Photo gallery]
- [http://www.tursiops.org/ Tursiops.org: Current Dolphin-related news]
- [http://www.wilddolphin.org/dolphinpictures.htm Wild Dolphin Foundation; Hawaiian Spinner Dolphin pictures, videos, information and conservation]
- [http://www.pbs.org/wnet/nature/dolphins/index.html PBS NOVA: Dolphins: Close Encounters]
- [http://www.accobams.org/download/articles/population/Agazzi_etal_2004.pdf Common dolphin prey species in the eastern Ionian Sea]
- [http://www.whale-images.com/facts_about_dolphins.htm facts about dolphins]
- [http://www.omplace.com/omsites/discover/DOLPHINS/ OM Place] A pictorial comparitive chart. Category:Cetaceans ko:돌고래 ja:イルカ simple:Dolphin

Mammal



- Subclass Multituberculata (extinct)
  - Plagiaulacida
  - Cimolodonta
- Subclass Palaeoryctoides (extinct)
- Subclass Triconodonta (extinct)
- Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors)
  - Afrosoricida
  - Artiodactyla
  - Carnivora
  - Cetacea
  - Chiroptera
  - Cimolesta (extinct)
  - Creodonta (extinct)
  - Condylarthra (extinct)
  - Dermoptera
  - Desmostylia (extinct)
  - Embrithopoda (extinct)
  - Hyracoidea
  - Insectivora
  - Lagomorpha
  - Litopterna (extinct)
  - Macroscelidea
  - Mesonychia (extinct)
  - Notoungulata (extinct)
  - Perissodactyla
  - Pholidota
  - Plesiadapiformes (extinct)
  - Primates
  - Proboscidea
  - Rodentia
  - Scandentia
  - Sirenia
  - Taeniodonta (extinct)
  - Tillodontia (extinct)
  - Tubulidentata
  - Xenarthra
- Subclass Marsupialia
  - Dasyuromorphia
  - Didelphimorphia
  - Diprotodontia
  - Microbiotheria
  - Notoryctemorphia
  - Paucituberculata
  - Peramelemorphia
- Subclass Monotremata
  - Monotremata The mammals are the class of vertebrate animals characterized by the presence of mammary glands, which in females produce milk for the nourishment of young; the presence of hair or fur; and which have endothermic or "warm-blooded" bodies. The brain regulates endothermic and circulatory systems, including a four-chambered heart. Mammals encompass some 5500 species, distributed in about 1200 genera, 152 families and up to 46 orders, though this varies depending on the classification scheme adopted. Phylogenetically, Mammalia is defined as all of the descendants of the last common ancestor of monotremes (e.g., echidnas) and therian mammals (placentals and marsupials).

Characteristics

While most mammals give birth to live young, there are a few mammals (the monotremes) that lay eggs. Live birth also occurs in a variety of non-mammalian species, such as guppies and hammerhead sharks; thus it is not a distinguishing characteristic of mammals. Although all mammals are endothermic, so are birds and so this is also not a main defining feature. While monotremes do not have nipples, they do have mammary glands, meaning that they meet all conditions for inclusion in the class Mammalia. It should be noted that the current trend in taxonomy is to emphasize common ancestry; the diagnostic characteristics are useful for identifying this ancestry, but if, for example, a cetacean were found that had no hair at all, it would still be classified as a mammal. Mammals have three bones in each ear and one (the dentary) on each side of the lower jaw; all other vertebrates with ears have one bone (the stapes) in the ear and at least three on each side of the jaw. A group of therapsids called cynodonts had three bones in the jaw, but the main jaw joint was the dentary and the other bones conducted sound. The extra jaw bones of other vertebrates are thought to be homologous with the malleus and incus of the mammal ear. All mammalian brains possess a neocortex. This brain region is unique to mammals. Mammals have integumentary systems made up of three layers: the outermost epidermis, the dermis, and the hypodermis. The epidermis is typically ten to thirty cells thick, its main function being to provide a waterproof layer. Its outermost cells are constantly lost; its bottommost cells are constantly dividing and pushing upward. The middle layer, the dermis, is fifteen to forty times thicker than the epidermis. The dermis is made up of many components such as bony structures and blood vessels. The hypodermis is made up of adipose tissue. Its job is to store lipids, and to provide cushioning and insulation. The thickness of this layer varies widely from species to species. Most mammals are terrestrial, but a number are aquatic, including sirenia (manatees and dugongs) and the cetaceans (dolphins and whales). Whales are the largest of all animals. There are semi-aquatic species such as seals which come to land to breed but spend the majority of the time in water. True flight has evolved only once in mammals, the bats; mammals such as flying squirrels and flying lemurs are actually gliding animals. No mammals have hair naturally blue or green in colour. Some cetaceans, along with the mandrills appear to have shades of blue skin. Many mammals are indicated as having blue hair or fur, but in all cases, it will be found to be a shade of grey. The two-toed sloth can seem to have green fur, however, this colour is caused by algae growths.

Origins

Mammals belong among the amniotes, and in particular to a group called the synapsids, distinguished by the shape of their skulls, in particular the presence of a single hole where jaw muscles attach, called temporal fenestra. In comparison, dinosaurs, birds, and most reptiles are diapsids, with two temporal fenestrae; and turtles, with no temporal fenestra, are anapsids. From synapsids came the first mammal precursors, therapsids, and more specifically the eucynodonts, 220 million years ago (mya) during the Triassic period. Pre-mammalian ears began evolving in the late Permian to early Triassic to their current state, as three tiny bones (incus, malleus, and stapes) inside the skull; accompanied by the transformation of the lower jaw into a single bone. Other animals, including reptiles and pre-mammalian synapsids and therapsids, have several bones in the lower jaw, some of which are used for hearing; and a single ear-bone in the skull, the stapes. This transition is evidence of mammalian evolution from reptilian beginnings: from a single ear bone, and several lower jaw bones (for example the sailback pelycosaur, Dimetrodon) to progressively smaller "hearing jaw bones" (for example the cynodont, Probainognathus), and finally (possibly with Morganucodon, but definitely with Hadrocodium), true mammals with three ear bones in the skull and a single lower jaw bone. Hence pelycosaurs and cynodonts are sometimes called "mammal-like reptiles", though this is strictly incorrect since in modern parlance these two are not reptiles, but rather synapsids. During the Mesozoic Period mammals diversified into four main groups: multituberculates, monotremes, marsupials, and placentals. Multituberculates went extinct during the Oligocene, about 30 million years ago, but the three other mammal groups are all represented today. Most early mammals remained small and shrew-like throughout the Mesozoic, but rapidly developed into larger more diverse forms following the Cretaceous-Tertiary extinction event 65 mya. The names "Prototheria", "Metatheria" and "Eutheria" expressed the theory that Placentalia were descendants of Marsupialia, which were in turn descendants of Monotremata, but this theory has been refuted. However, Eutheria and Metatheria are often used in paleontology, especially with regards to mammals of the Mesozoic. Mammal evolutionary progression is below:
- Jawless fish: Cambrian period to mid Ordovician periods
- Bony fish: mid-Ordovician period to late Devonian period
- Amphibians: late Devonian period to early Carboniferous period
- Reptiles: late Carboniferous period
- Pelycosaurs (synapsids, or "mammal-like reptiles"): late Carboniferous period to very early Triassic period
- Cynodonts: Permian-Triassic
- Mammals: mid-Triassic period to today

In the Mesozoic

Most early mammals were small shrew-like animals that fed on insects. However, in January 2005, the discovery was reported of two fossils of Repenomamus around 130 million years old, one more than a meter in length, the other having remains of a baby dinosaur in its stomach (Nature, Jan. 15, 2005 [http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v433/n7022/full/433116b_fs.html].) The earliest mammals include:
- Eozostrodon: Triassic and Jurassic
- Deltatheridium: Cretaceous
- Jeholodens: mid-Cretaceous
- Megazostrodon: late Triassic and early Jurassic
- Triconodont: Triassic to Cretaceous
- Zalambdalestes: late Cretaceous Although mammals existed alongside the dinosaurs, mammals only began to dominate after the mass extinction of the dinosaurs 65 mya, in the Cenozoic.

In the Paleocene

During the next 8 million years, the Paleocene period (64–58 mya), mammals exploded into the ecological niches left by the extinction of the dinosaurs. Small rodent-like mammals still dominated, but medium and larger-sized mammals evolved.
- Ptilodus: multituberculate
- Pucadelphys andinus: an opposum-like marsupial
- Purgatorius: a primate-like mammal, placental
- Ectoconus: an early hoofed mammal, placental

Classification

Main article: Mammal classification George Gaylord Simpson's classic "Principles of Classification and a Classification of Mammals" (AMNH Bulletin v. 85, 1945) was the original source for the taxonomy listed here. Simpson laid out a systematics of mammal origins and relationships that was universally taught until the end of the 20th century. Since Simpson's 1945 classification, the paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics. Though field work gradually made Simpson's classification outdated, it remained the closest thing to an official classification of mammals.

Standardized textbook classification

A somewhat standardized classification system has been adopted by most current mammalogy classroom textbooks. The following taxonomy of extant and recently extinct mammals is taken from Vaughan et al. (2000). Class Mammalia
- Subclass Prototheria - monotremes: platypus and echidnas
- Subclass Theria - live-bearing mammals
  - Infraclass Metatheria - marsupials
  - Infraclass Eutheria - placentals

McKenna/Bell classification

In 1997, the mammals were comprehensively revised by Malcolm C. McKenna and Susan K. Bell, which has resulted in the "McKenna/Bell classification". McKenna and Bell, Classification of Mammals: Above the species level, (1997) is the most comprehensive work to date on the systematics, relationships, and occurrences of all mammal taxa, living and extinct, down through the rank of genus. The new McKenna/Bell classification was quickly accepted by paleontologists. The authors work together as paleontologists at the American Museum of Natural History, New York. McKenna inherited the project from Simpson and, with Bell, constructed a completely updated hierarchical system, covering living and extinct taxa that reflects the historical genealogy of Mammalia. The McKenna/Bell hierarchical listing of all of the terms used for mammal groups above the species includes extinct mammals as well as modern groups, and introduces some fine distinctions such as legions and sublegions (ranks which fall between classes and orders) that are likely to be glossed over by the layman. The published re-classification forms both a comprehensive and authoritative record of approved names and classifications and a list of invalid names. Click on the highlighted link for a [http://nasa.utep.edu/chih/chklist/mammals/keys/mammtab.htm table comparing the traditional and the new McKenna/Bell classifications of mammals] Extinct groups are represented by †. Class Mammalia
- Subclass Prototheria: monotremes: platypuses and echidnas
- Subclass Theriiformes: live-bearing mammals and their prehistoric relatives
  - Infraclass †Allotheria: multituberculates
  - Infraclass †Triconodonta: triconodonts
  - Infraclass Holotheria: modern live-bearing mammals and their prehistoric relatives
    - Supercohort Theria: live-bearing mammals
      - Cohort Marsupialia: marsupials
      -
- Magnorder Australidelphia: Australian marsupials and the monito-del-monte
      -
- Magnorder Ameridelphia: New World marsupials
      - Cohort Placentalia: placentals
      -
- Magnorder Xenarthra: xenarthrans
      -
- Magnorder Epitheria: epitheres
      -
  - Grandorder Anagalida: lagomorphs, rodents, and elephant shrews
      -
  - Grandorder Ferae: carnivorans, pangolins, creodonts, and relatives
      -
  - Grandorder Lipotyphla: insectivorans
      -
  - Grandorder Archonta: bats, primates, colugos, and tree shrews
      -
  - Grandorder Ungulata: ungulates
      -
    - Order Tubulidentata incertae sedis: aardvark
      -
    - Mirorder Eparctocyona: condylarths, whales, and artiodactyls
      -
    - Mirorder †Meridiungulata: South American ungulates
      -
    - Mirorder Altungulata: perissodactyls, elephants, manatees, and hyraxes

Molecular classification of mammals

Molecular studies based on DNA analysis have suggested new relationships among mammal families over the last few years. The most recent classification systems based on molecular studies have proposed four groups or lineages of placental mammals. Molecular clocks suggest that these clades diverged from early common ancestors in the Cretaceous, but fossils have not been found to corroborate this hypothesis. These molecular findings are consistent with mammal zoogeography: The first divergence was that of the Afrotheria 110–100 mya. The Afrotheria proceeded to evolve and diversify in the isolation of the African-Arabian continent. The Xenarthra, isolated in South America, diverged from the Boreoeutheria approximately 100–95 mya. The Boreoeutheria split into the Laurasiatheria and Euarchontoglires between 95 and 85 mya; both of these groups evolved on the northern continent of Laurasia. After tens of millions of years of relative isolation, Africa-Arabia collided with Eurasia, exchanging Afrotheria and Boreoeutheria. The formation of the Isthmus of Panama linked South America and North America, which facilitated the exchange of mammal species in the Great American Interchange. The traditional view that no placental mammals reached Australasia until about 5 million years ago when bats and murine rodents arrived has been challenged by recent evidence and may need to be reassessed. It should however be noted that these molecular results are still controversial because they are not reflected by morphological data and thus not accepted by many systematists.
- Group I: Afrotheria
  - Order Macroscelidea: elephant shrews (Africa).
  - Order Afrosoricida
  - Order Tubulidentata: aardvark (Africa south of the Sahara).
  - Clade Paenungulata
    - Order Hyracoidea: hyraxes, dassies (Africa, Arabia).
    - Order Proboscidea: elephants (Africa, Southeast Asia).
    - Order Sirenia
- Group II: Xenarthra
  - Order Xenarthra: sloths and anteaters (Neotropical) and armadillos (Neotropical and Nearctic)
- Clade Boreoeutheria
  - Group III Euarchontoglires
    - Superorder Euarchonta
      - Order Scandentia: tree shrews (Southeast Asia).
      - Order Dermoptera: flying lemurs or colugos (Southeast Asia).
      - Order Primates: lemurs, bushbabies, monkeys, apes (cosmopolitan).
    - Superorder Glires
      - Order Lagomorpha: pikas, rabbits, hares (Eurasia, Africa, Americas).
      - Order Rodentia: rodents (cosmopolitan)
  - Group IV: Laurasiatheria
    - Order Insectivora: eulipotyphlan insectivorans
    - Order Chiroptera: bats (cosmopolitan)
    - Order Cetartiodactyla: cosmopolitan; includes former orders Cetacea (whales, dolphins and porpoises) and Artiodactyla (even-toed ungulates, including pigs, hippopotamus, camels, giraffe, deer, antelope, cattle, sheep, goats).
    - Clade Zooamata
      - Order Perissodactyla: odd-toed ungulates
      - Clade Ferae
      -
- Order Pholidota: pangolins, scaly anteaters (Africa, South Asia).
      -
- Order Carnivora: carnivorans (cosmopolitan)

Classification system used in related articles

In light of all the options available, the following classification system has been adopted for use in related articles. Class Mammalia
- Subclass/Order Monotremata: egg-laying mammals
  - Order Monotremata: echidnas and platypus
- Subclass Marsupialia: marsupials
  - Order Didelphimorphia: New World opossums
  - Order Paucituberculata: shrew opossums
  - Order Microbiotheria: Monito del Monte
  - Order Dasyuromorphia: marsupial carnivores
  - Order Notoryctemorphia: marsupial mole
  - Superorder Syndactyla: syndactylous marsupials
    - Order Peramelemorphia: bandicoots and bilbies
    - Order Diprotodontia: koalas, wombats, kangaroos, possums, etc.
- Subclass Placentalia
  - Order Xenarthra: sloths, anteaters, armadillos
  - Order Pholidota: pangolins
  - Superorder Glires
    - Order Rodentia: rodents
    - Order Lagomorpha: rabbits, hares, and pikas
  - Order Macroscelidea: elephant shrews
  - Superorder Archonta:
    - Order Primates: primates
    - Order Scandentia: tree shrews
    - Order Chiroptera: bats
    - Order Dermoptera: colugos
  - Order Insectivora: shrews, tenrecs, moles, hedgehogs, etc.
  - Order Carnivora: dogs, cats, weasels, seals, etc.
  - Superorder Ungulata: ungulates
    - Order Tubulidentata: aardvark
    - Order Hyracoidea: hyraxes
    - Order Proboscidea: elephants
    - Order Sirenia: manatees, dugong
    - Order Perissodactyla: horses, tapirs, rhinoceroses
    - Order Artiodactyla: even-toed ungulates
    - Order Cetacea: whales

References


- McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8
- Nowak, Ronald M. 1999. Walker's Mammals of the World, 6th edition. Johns Hopkins University Press, 1936 pp. ISBN 0-801-85789-9
- Simpson, George Gaylord. 1945. "The principles of classification and a classification of mammals". Bulletin of the American Museum of Natural History, 85:1–350.
- Springer, Mark S., Michael J. Stanhope, Ole Madsen, and Wilfried W. de Jong. 2004. "Molecules consolidate the placental mammal tree". Trends in Ecology and Evolution, 19:430–438. ([http://www.zi.ku.dk/evolbiology/courses/ME04/7_9/springer200-phyl.pdf pdf version])
- Vaughan, Terry A., James M. Ryan, and Nicholas J. Capzaplewski. 2000. Mammalogy: Fourth Edition. Saunders College Publishing, 565 pp. ISBN 0-030-25034-X (Brooks Cole, 1999)
- Wilson, Don E., and Deeann M. Reeder (eds). 1993. Mammal Species of the World. Smithsonian Institution Press, 1206 pp. ISBN 1-560-98217-9

See also


- List of mammals
- List of regional mammals lists
- List of prehistoric mammals
- Mammal classification

External links


- [http://www.nceas.ucsb.edu/~alroy/nafmsd.html North American Fossil Mammal Systematics Database.]
- [http://paleocene-mammals.de/ Paleocene Mammals], a site covering the rise of the mammals
- [http://www.enchantedlearning.com/subjects/mammals/Evolution.shtml Evolution of Mammals], a brief introduction to early mammals
- [http://home.arcor.de/ktdykes/mesomamm.htm The Evolution of Mesozoic Mammals, a Rough Sketch], an informal introduction
- [http://www.carnegiemnh.org/research/news.html Carnegie Museum of Natural History], some discoveries of early mammal fossils
- [http://www.geocities.com/mammal_taxonomy/index.html Mammal Taxonomy], database of mammals of the world, updated each month
- [http://nmnhgoph.si.edu/msw/ Mammal Species of the World], searchable online version of 2nd edition (1993) of Mammal Species of the World zh-min-nan:Chhī-leng tōng-bu̍t ko:포유류 ms:Mamalia ja:哺乳類 simple:Mammal th:สัตว์เลี้ยงลูกด้วยนม

Whale

Whales are the largest species of exclusively aquatic placental mammals, members of the order Cetacea, which also includes dolphins and porpoises. They are the largest mammals, the largest vertebrates, and the largest animals in the world. The term whale is ambiguous: it can refer to all cetaceans, to just the larger ones, or only to members of particular families within the order Cetacea. The latter definition is the one followed here. Whales are those cetaceans which are neither dolphins (i.e. members of the families Delphinidae or Platanistoidea), nor porpoises. This can lead to some confusion because Orcas ("Killer Whales") and Pilot Whales have "whale" in their name, but they are dolphins for the purpose of classification.

Origins and taxonomy

Whales, along with most dolphins and porpoises, are descendants of land-living mammals, most likely of the Artiodactyl order. They entered the water roughly 50 million years ago. See evolution of cetaceans for the details [http://news.bbc.co.uk/1/hi/sci/tech/1974869.stm]. Cetaceans are divided into two suborders:
- The baleen whales are characterized by the baleen, a sieve-like structure in the upper jaw made of keratin, which they use to filter plankton from the water. They are the largest whales.
- The toothed whales have teeth and prey on fish and/or squid. An outstanding ability of this group is to sense their surrounding environment through echolocation. A complete up-to-date taxonomical listing of all cetacean species, including all whales, is maintained at the Cetacea article.

Anatomy

Like all mammals, whales breathe air into lungs, are warm-blooded (that is, endothermic), breast-feed their young, and have some (although very little) hair. The whales' ancestors lived on land, and their adaptions to a fully aquatic life are quite striking: The body is fusiform, resembling the streamlined form of a fish. The forelimbs, also called flippers, are paddle-shaped. The end of the tail holds the fluke, or tail fins, which provide propulsion by vertical movement. Although whales generally do not possess hind limbs, some whales (such as sperm whales, baleen whales, and humpback whales) have been seen having rudimentary hind limbs; some even with feet and digits. Most species of whale bear a fin on their backs known as a dorsal fin. Beneath the skin lies a layer of fat, the blubber. It serves as an energy reservoir and also as insulation. Whales have a four-chambered heart. The neck vertebrae are fused in most whales, which provides stability during swimming at the expense of flexibility. Whales breathe through blowholes, located on the top of the head so the animal can remain submerged. Baleen whales have two; toothed whales have one. When exhaling after a dive, a spout can be seen from the right perspective, the shape of which differs among the species. Whales have a unique respiratory system that lets them stay underwater for long periods of time without taking in any oxygen. Some whales, such as the Sperm Whale, can stay underwater for up to two hours holding a single breath. Especially noteworthy is the Blue Whale, the largest known animal that has ever lived. It may be up to 30 meters long and weigh 180 tons.

Behaviour

Blue Whale Main article: Whale behaviour Whales are broadly classed as predators, but their food ranges from microscopic plankton to very large fish. Males are called bulls; females, cows. The young are called calves. Because of their environment (and unlike many animals), whales are conscious breathers: They have to decide when to breathe. So how do they sleep? All mammals sleep, and so do whales, but they cannot afford to fall into an unconscious state for too long, since they need to be conscious in order to breathe. The solution is that only one hemisphere of their brains sleeps at the time, so that whales are never completely asleep, but still get the rest they need. Whales "sleep" around 8 hours a day. Whales also communicate with each other using beautiful lyrical type sounds. Being so large and powerful these sounds are also extremely loud and can be heard for many miles. They have been known to generate about 20,000 acoustic watts of sound at 163 decibels.
- [http://www.makeitlouder.com/Decibel%20Level%20Chart.txt table of sound decibel levels] Whale females give birth to a single calf. Nursing time is long (more than one year in many species), which is associated with a strong bond between mother and young. In most whales reproductive maturity occurs late, typically at seven to ten years. This strategy of reproduction spawns few offspring, but provides each with a high rate of survival. The genital organs are retracted into cavities of the body during swimming, so as to be streamlined and reduce drag. Most whales do not maintain fixed partnerships during mating; in many species the females have several mates each season. At birth the newborn is delivered tail-first, so the risk of drowning is minimized. Whale mothers nurse the young by actively squirting the fatty milk into their mouths, a milk that according to German naturalist Dieffenbach, bears great similarities to cow's milk.

Whale intelligence

For more material in this area, focusing more on dolphins, see cetacean intelligence. Many people believe that cetaceans in general, and whales in particular, are highly intelligent animals. This belief has become a central argument against whaling (killing whales for food or other commercial reasons). There is no universally agreed definition of "intelligence." One commonly used definition is "the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience." Proponents of whale intelligence cite the social behavior of whales and their apparent capacity for language as evidence of a sophisticated intellect. Given the radically different environment of whales and humans, and the size of whales compared to (say) dolphins or chimpanzees, it is extremely difficult to test these views experimentally. One traditional indicator of intelligence is brain capacity, since humans have bigger brains than most other animals. Whales have the largest brain of any animal. A typical sperm whale brain weighs about 7.8 kg, whereas a typical human brain weighs about 1.5 kg. While it may seem that this would indicate that five times greater intelligence, in mammals brain size is in approximate ratio to body size, and most of the extra capacity is used to manage the larger body. A more precise indicator is the brain-body ratio: the size of the brain compared to body mass. Here humans have a decisive advantage. A human brain comprises about 2% of the human body mass, while the sperm whale's brain comprises only 0.02% of its body mass. A cow's brain is four times as large as a whale's on this measurement. On the other hand, a large proportion of a whale's body mass is blubber, which requires no brain power, and this distorts the ratio somewhat. Nevertheless, it is clear that brain size is not a decisive criterion. Hummingbirds have an even higher brain-to-body ratio than humans. The next consideration is the structure of the brain. It is generally agreed that the growth of the neocortex, both absolutely and relative to the rest of the brain, during human evolution, has been responsible for the evolution of intelligence, however defined. In most mammals the neocortex has six layers, and its different functional areas (vision, hearing, etc) are sharply differentiated. The whale neocortex, on the other hand, has only five layers, and there is little differentiation of these layers according to function. This has led some to argue that the whale brain has not significantly evolved since the distant ancestors of the whale took to a marine lifestyle about 50 million years ago. From an evolutionary point of view, this is consistent with the principles of natural selection. Intelligence does not arise spontaneously: like any other animal capacity, it evolves under the pressure of the animal's environment. The human brain has evolved under the pressure of natural selection in a hostile terrestrial environment. The key primate characteristics - bipedalism and the opposable thumb - gave the early hominids the ability to manipulate their environment through the use of technology (by making tools). This unique adaptation created a virtuous cycle: tool-making gave those hominids with larger brains a decisive evolutionary advantage, leading to larger and more sophisticated brains, and thus to more tool-making. This process explains the exponential growth of hominid intelligence over the past million years. By contrast, the whale has faced no such environmental stimuli to brain evolution. Whales live in an unchanging and benign environment with few natural predators. Their sole adaptation to their marine environment has been increasing size. The whale's lifestyle consists of swimming and eating, tasks which fish perform perfectly competently with very small brains. From an evolutionary point of view, there is no reason for whales to have evolved intelligence, since their survival does not require them to perform any tasks for which intelligence is necessary. It is certainly true that whales have a sophisticated social system, and that their communication system may contain some of the elements of true language, although our knowledge of whale communications is not very advanced. These capacities are sometimes confused with intelligence. But many other animals, including insects, have complex social systems, and many others, such as birds, have sophisticated communications. Whales also have very acute hearing, which gives them advanced echo-location capacities analogous to sonar - but so do bats. All this has led many (though far from all) zoologists to the conclusion that there is no convincing evidence for superior whale intelligence.

Whales and Humans

Main article Whaling Most species of large whales are endangered as a result of large-scale whaling during the nineteenth and twentieth centuries. For centuries large whales have been hunted for oil, meat, baleen and ambergris (a perfume ingredient from the intestine of sperm whales). Until the middle of the 20th century, whaling left many populations nearly or fully extinct. The International Whaling Commission introduced an open ended moratorium on all commercial whaling in 1986. For various reasons some exceptions to this moratorium exist; current whaling nations are Norway, Iceland and Japan and the aboriginal communities of Siberia, Alaska and northern Canada. For details, see whaling. Several species of small whales are caught as bycatch in fisheries for other species. In the tuna fishery in the Eastern Tropical Pacific thousands of dolphins used to drown in purse-seine nets, until measures to prevent this were introduced. Fishing gear and deployment modifications, and eco-labelling (dolphin-safe brands of canned tuna), have contributed to an estimated 96% reduction in the mortality of dolphins by tuna fishing vessels in recent years. In many countries, small whales are still hunted for food, oil, meat or bait. Environmentalists have long argued that some cetaceans including whales are endangered by sonar used by advanced navies. In 2003 British and Spanish scientists have suggested in Nature that the sonar is connected to whale beachings and to signs that the beached whales have experienced decompression sickness (see [http://news.bbc.co.uk/2/hi/science/nature/3173942.stm a BBC report about the Nature article] or [http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v425/n6958/full/425575a_fs.html the Nature article itself (requires subscription)]). Mass whale beachings do occur amongst many species (most of them are beaked whales that make use of echolocation system for deep diving). The frequency and size of beachings around the world, recorded over the last 1000 years in religious tracts and more recently in scientific surveys, has been used to estimate the changing population size of various whale species by assuming that the proportion of the total whale population beaching in any one year is constant (reference?). Despite the concerns raised about sonar which may invalidate this assumption, this population estimate technique is still popular today. Researchers in the area (Talpalar & Grossman, 2005) support that is the combination between high pressure environment of deep-diving together with the disturbing effect of the sonar which causes decompression sickness and stranding of whales. Thus, an exaggerated startle response occurring during deep diving may alter orientation cues and produce rapid ascension. This hypothesis is based on direct effect of high pressure in the central nervous system of mammals: depression of synaptic activity and increased neural excitability. Following public concern, the US Defense department has been ordered by the US judiciary to strictly limit use of its Low Frequency Active Sonar during peacetime. Attempts by the UK-based Whale and Dolphin Conservation Society to obtain a public inquiry into the possible dangers of the Royal Navy's equivalent (the "2087" sonar launched in December 2004) have so far failed. The European Parliament on the other hand has requested that EU members resist using the powerful sonar system until an environmental impact study has been carried out. [http://home.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20041206005421&newsLang=en] Conservationists are also concerned that seismic testing used for oil and gas exploration may also damage the hearing and echolocation capabilities of whales. They also suggest that disturbances in magnetic fields caused by the testing may also be responsible for beaching. [http://www.sustainability.ca/Docs/Impact%20of%20Seismic%20Surveys%20on%20Whales.pdf?CFID=9951883&CFTOKEN=72165442 See e.g. Seismic testing and the impacts of high intensity sound on whales, Lindy Weilgart, Department of Biology Dalhouise University (PDF format)] or a [http://whales.greenpeace.org/news/3aug2001.html typical press release from Greenpeace on the issue]

Whales in culture

The King James Version of the Bible mentions whales four times: "And God created great whales" (Genesis 1:21); "Am I a sea, or a whale, that thou settest a watch over me? (Job 7:12); "Thou art like a young lion of the nations, and thou art as a whale in the seas (Ezekiel 32:2); and "For as Jonas [sic] was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth" (Matthew 12:40). Nevertheless, the passages in question do not unambiguously refer to whales; modern translations tend to use other terms; for example the New International Version uses "creatures of the sea"; "monster of the deep"; "monster"; and "huge fish" respectively. The Book of Jonah (in the King James and some other translations) does not use the word "whale" at all, referring throughout to a "fish" or a "great fish": "Now the LORD had prepared a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights." (Jonah 1:17). This detail was used to dramatic effect in Clarence Darrow's cross-examination of fundamentalist William Jennings Bryan in the 1925 Scopes Trial, as depicted in the drama "Inherit the Wind" by Jerome Lawrence and Robert E. Lee. The hunting of whales is the subject of one of the classics of the English language literary canon, Herman Melville's Moby-Dick. Melville classed whales as "a spouting fish with a horizontal tail", despite science suggesting otherwise the previous century. Melville acknowledged "the grounds upon which Linnaeus would fain have banished the whales from the waters" but says that when he presented them to "my friends Simeon Macey and Charley Coffin, of Nantucket ... they united in the opinion that the reasons set forth were altogether insufficient. Charley profanely hinted they were humbug." Melville's book is an extraordinary work, part adventure story, part metaphysical allegory, and part natural history; it is essentially a complete summary of nineteenth-century knowledge about the biology, ecology and cultural significance of whales. Some cultures associate some level of divinity with the whale, such as in some places in Ghana and the Vietnamese, who occasionally hold funerals for beached whales, a throwback to Vietnam's ancient sea-based Austroasiatic culture. Festivals celebrating whales have sprung in both Sitka and Kodiak Alaska. They feature speakers on marine biology and celebrate the creatures with art, music, whale-watching cruises, and symposiums.

See also


- Cetacea (contains a species list)
- Baleen whale
- Toothed whale
- Dorsal fin
- Whaling
- International Whaling Commission
- Exploding whale
- Whale fall
- List of whale species
- Sitka Whale Fest

Further reading


- Whales, Dolphins and Porpoises by Mark Carwardine, published by Dorling Kindersley, 2000. ISBN 0-7513-2781-6. Introductory guide to cetaceans.

External links


- [http://www.bigvolcano.com.au/human/whaling.htm Australian Whaling History]
- [http://news.bbc.co.uk/1/hi/sci/tech/239966.stm Oldest whale fossil confirms amphibious origins]
- [http://whales.greenpeace.org/ Greenpeace] - anti-whaling site
- [http://www.highnorth.no/Default.asp High North Alliance] - pro-whaling site
- [http://www.cetacea.org/ Cetacea]
- [http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html Whale Evolution]
- [http://www.whale-images.com Whale and Dolphin images]
- [http://whaleofatime.com/forum Whale Of A Time Forum] Whales, Dolphins, Porpoises and Cetaceans. Category:Cetaceans ja:クジラ目 ms:Ikan paus

Ancient Greek

Ancient Greek refers to the stage in the history of the Greek language corresponding to Classical Antiquity, which normally applies to two periods of Greek history: Archaic and Classical Greece. The Ancient era of Greek history normally includes also the Hellenistic (post-Classic) age; however, that period formally composes its own stage in the Greek Language known as Hellenistic Greek. For information on the Greek language prior to the creation of the Greek alphabet, see articles Mycenaean Greek and Proto-Greek.

Dialects of Ancient Greek

The Greek language had started shaping in local forms even before the settling of the Greek-speaking tribes into Greece, yet the actual dialectic variation took place afterwards. Throughout history the Greek language is presented in a number of dialects that did not apply on fixed geographical borders, and even if it did, those borders would be constantly altered because of the frequent migrations of the Hellenic peoples. According to its linguistic variations, the Ancient Greek language of the Archaic and Classic periods is composed by the following symbolic dialectic branches: The dialects of the pre-classical and classical period appear documented in writing beginning in the 8th century BC, and they certainly developed well before this date. The most standard formulation currently for the pre-classical and classical dialects is four or five major groups: # Northwest Greek (including Doric, and possibly Ancient Macedonian) # Aeolic (including Boeotian, Lesbian, Thessalian, and Aegean/Asiatic Aeolic subdivisions) # Attic-Ionic # Arcado-Cyprian # and possibly Pamphylian As each of the above dialectic branches is broken down to its individual dialects, each dialect can in turn be divided into countless local idioms. The information provided in the dialect-specific articles is a general linguistic description that is confined to the main characteristics of the Common form (Koine) of each dialect, without getting into detail about their numerous idiomatic variations. In that respect, the article on Doric describes the "Common" form of Doric as it is seen, e.g., in Pindar's poetry, which differs from local forms such as Laconian, Cretan, Sicilian or even Theban Doric. The Arcado-Cyprian group appears to be closest to Mycenaean Greek, and is likely its direct descendant. Northwest/Doric is the most distinct from the others. Controversy on the early history of Greek dialects generally focuses on the nature of Aeolic and Attic-Ionic—with various configurations of independent development or relations to Mycenaean or Northwest/Doric proposed. The relations between the dialects are likely obscured by significant amounts of influence on each other. After the conquests of Alexander the Great in the 4th century BC, a new international dialect known as Koine or Common Greek developed, largely based on Attic Greek, but with influence from other dialects. This dialect slowly replaced most of the older dialects, although Doric dialect has survived to the present in the form of the Tsakonian and Southern Italian dialect of Modern Greek. Doric has also passed down its Aorist terminations into most verbs of Demotic Greek. By about the 7th century AD., the Koine had slowly metamorphosized into Medieval Greek.

Sound changes

These sound changes since Proto-Greek affect most or all Ancient Greek dialects:
- Syllabic /r/, /l/ become /ro/ and /lo/ in Mycenean Greek and Aeolic Greek; otherwise /ra/ and /la/, but /ar/ and /al/ before resonants and analogously.
- Loss of /h/ from original /s/ (except initially) and of /j/.
- Loss of /w/ in many dialects (later than loss of /h/ and /j/).
- Loss of labiovelars, which were converted (mostly) into labials, sometimes into dentals or velars.
- Contraction of adjacent vowels resulting from loss of /h/ and /j/ (and, to a lesser extent, from loss of /w/); more in Attic Greek than elsewhere.
- Rise of a distinctive circumflex accent, resulting from contraction and certain other changes.
- Limitation of the accent to the last three syllables, with various further restrictions.
- Loss of /n/ before /s/ (incompletely in Cretan Greek), with compensatory lengthening of the preceding vowel. Note that /w/ and /j/, when following a vowel and not preceding a vowel, combined early on with the vowel to form a diphthong and were thus not lost. The loss of /h/ and /w/ after a consonant were often accompanied by compensatory lengthening of a preceding vowel. The loss of /j/ after a consonant was accompanied by a large number of complex changes, including diphthongization of a preceding vowel or palatalization or other change to a directly preceding consonant. Some examples:
- /pj/, /bj/, /phj/ -> /pt/
- /lj/ -> /ll/
- /tj/, /thj/, /kj/, /khj/ -> /s/ when following a consonant; otherwise /tt/ (Attic), /ss/ (Ionic)
- /gj/, /dj/ -> /zd/
- /mj/, /nj/, /rj/ -> /j/ is transposed before consonant and forms a diphthong with the preceding vowel
- /wj/, /sj/ -> /j/, forming a diphthong with the preceding vowel The results of vowel contraction were complex and differed from dialect to dialect. Such contractions occur in the inflection of a number of different noun and verb classes and are among the most difficult aspects of Ancient Greek grammar. They were particularly important in the large class of contracted verbs, denominative verbs formed from nouns and adjectives ending in a vowel. (In fact, the reflex of contracted verbs in Modern Greek—i.e., the set of verbs derived from Ancient Greek contracted verbs—represents one of the two main classes of verbs in that language.)

Sounds

The pronunciation of Post-Classic Greek changed considerably from Ancient Greek, although the orthography still reflects features of the older language (see W. Sidney Allen, Vox Graeca – a guide to the pronunciation of Classical Greek). For a detailed description on the phonology changes from Ancient to Hellenistic periods of the Greek language, see the article on Koine Greek. The examples below are intended to represent Attic Greek in the 5th century BC. Although ancient pronunciation can never be reconstructed with certainty, Greek in particular is very well documented from this period, and there is little disagreement among linguists as to the general nature of the sounds that the letters represented.

Vowels

Short vowels

The short e (ε in Greek orthography) is shown in the table as mid close vowel , but it may have been nearer to .
  Front Back
Close unrounded  
Close rounded  
Close-mid
Open  

Long Vowels

The [] (ου in Greek orthography) probably changed to [] by the fourth century.
  Front Back
Close unrounded  
Close rounded  
Close-mid
Open-mid
Open  

Consonants

Note: [z] was an allophone of [s], used before voiced consonants, and in particular in the combination [zd] written as zeta (ζ). The [] (voiceless r) written as rho with a rough breathing () was probably an allophone of [r].

Consonant classes

There are three main classes of consonants:
- Stops. This include three subclasses: velars (k, g, kh), labials (p, b, ph), and dentals (t, d, th).
- Sonorants are m, n, l, r.
- Fricatives are s and h.

Consonant contractions

In verb conjugation, one consonant often comes up against the other. Various sandhi rules apply. Rules:
- Most basic rule: When two sounds appear next to each other, the first assimilates in voicing and aspiration to the second.
  - This applies fully to stops. Fricatives assimilate only in voicing, sonorants do not assimilate.
- Before an s (future, aorist stem), velars become k, labials p, and dentals disappear.
- Before a th (aorist passive stem), velars become kh, labials ph, dentals s.
- Before an m (perfect middle first-singular, first-plural, participle), velars become g, nasal+velar becomes g, labials m, dentals and n become s, other sonants remain.

Compensatory lengthening

There are different schemes for compensatory lengthening, depending on where it happens. The differences are in whether a becomes ā or ē, and whether e and o become the closed values ei /eː/ and ou /oː/ or the open values ē /ɛː/ and ō /ɔː/.

Augment

The indicative of past tenses adds (conceptually, at least) a prefix /e-/. This was probably originally a separate word, meaning something like "then", added because tenses in PIE had primarily aspectual meaning. The augment is added to the indicative of the aorist, imperfect and pluperfect, but not to any of the other forms of the aorist (no other forms of the imperfect and pluperfect exist). There are two kinds of augment in Greek, syllabic and quantitative. The syllabic augment is added to stems beginning with consonants, and simply prefixes e (stems beginning with r, however, add er). The quantitative augment is added to stems beginning with vowels, and involves lengthening the vowel:
- a, ā, e, ē -> ē
- i, ī -> ī
- o, ō -> ō
- u, ū -> ū
- ai -> ēi
- ei -> ēi or ei
- oi -> ōi
- au -> ēu or au
- eu -> ēu or eu
- ou -> ou Some verbs augment irregularly; the most common variation is e -> ei. The irregularity can be explained diachronically by the loss of s between vowels. The augment is sometimes omitted in poetry (Epic Greek). The augment sometimes substitutes for reduplication; see below.

Reduplication

All forms of the perfect, pluperfect and future perfect reduplicate the initial syllable of the verb stem. There are three types of reduplication:
- Syllabic reduplication: Most verbs beginning with a single consonant, or a cluster of a stop with a sonorant, add a syllable consisting of the initial consonant followed by e. An aspirated consonant, however, reduplicates in its unaspirated equivalent: this is often referred to as Grassman's Law.
- Augment: Verbs beginning with a vowel, as well as those beginning with a cluster other than those indicated previously (and occasionally for a few other verbs) reduplicate in the same fashion as the augment. Note that this remains in all forms of the perfect, not just the indicative.
- Attic reduplication: Some verbs beginning with an a, e or o, followed by a sonorant (or occasionally d or g), reduplicate by adding a syllable consisting of the initial vowel and following consonant, and lengthening the following vowel. Hence er -> erēr, an -> anēn, ol -> olōl, ed -> edēd. This is not actually specific to Attic Greek, despite its name. This originally involved reduplicating a cluster consisting of a laryngeal and sonorant; hence h₃l -> h₃leh₃l -> olōl with normal Greek development of laryngeals. (Forms with a stop were analogous.) Irregular duplication can be understood diachronically. For example, lambanō (root lab) has the perfect stem eilēpha (not
- lelēpha) because it was originally slambanō, with perfect seslēpha, becoming eilēpha through (semi-)regular change.

Grammatical forms

Ancient Greek, like all of the older Indo-European languages, is highly inflected. Ancient Greek is highly archaic in its preservation of Proto-Indo-European forms. Nouns (including proper nouns) have five cases (nominative, genitive, dative, accusative and vocative), three genders (masculine, feminine and neuter), and three numbers (singular, dual and plural). Verbs have four moods (indicative, imperative, subjunctive and optative), three voices (active, middle and passive), as well as three persons (first, second and third) and various other forms. Verbs are conjugated in four main tenses (present, aorist, perfect, and future), with a full complement of moods for each main tense, although there is no future subjunctive or imperative. (The distinction of the "tenses" in moods other than the indicative is actually mostly of aspect.) In addition, indicative forms of the imperfect and pluperfect exist. Infinitives and participles for all corresponding finite combinations of tense and voice, excluding the imperfect and pluperfect.

Nouns

Ancient Greek nouns have three numbers (singular, dual, and plural), three genders (masculine, feminine, and neuter) and five cases (nominative, genitive, dative, accusative and vocative). The two major noun declensions are the vowel declension and the consonant declension. The vowel declension is split into the alpha-declension and the omicron-declension. There is also the minor consonant declension.

Alpha Declension

The alpha declension is predominantly, but not exclusively, feminine. Nouns belonging to the alpha declension have stems ending in alpha, short or long. In certain circumstances the alpha may change its length or become eta. In the table below of feminine nouns there are three examples: long-alpha stem (-stems), short-alpha stems (-stems), and a stems which can end in eta (-stems).

Delphinidae


See text Oceanic dolphins are the members of the Delphinidae family of cetaceans. These aquatic mammals are related to whales and porpoises. As the name implies, these dolphins tend to be found in the open seas, unlike the river dolphins, although a few species such as the Irrawaddy Dolphin are coastal or riverine. Six of the larger species in the Delphinidae, the Orca and its relatives, are commonly called whales, rather than dolphins. They are also sometimes collectively known as "blackfish". The Delphinidae vary in size from 1.2 metres and 40 kg (Heaviside's Dolphin), up to 7 metres and 4.5 tonnes (the Orca). Most species weigh between about 50 and about 200 kg. They are found worldwide, mostly in the shallower seas of the continental shelves, and all are carnivores, mostly taking fish and squid.

Taxonomy


- ORDER CETACEA
- SUBORDER MYSTICETI
  - Family Eschrichtiidae: Gray Whale
  - Family Balaenopteridae: rorquals
  - Family Balaenidae: right whales and Bowhead Whale
  - Family Neobalaenidae: Pygmy Right Whale
- SUBORDER ODONTOCETI
  - Superfamily Platanistoidea: All river dolphins
    - Family Platanistidae: Indus and Ganges river dolphins
    - Family Lipotidae: Baiji (Yangtze River Dolphin)
    - Family Iniidae: Boto (Amazon River Dolphin)
    - Family Pontoporiidae: Franciscana (La Plata Dolphin)
    - Family Delphinidae
      - Genus Peponocephala
      -
- Melon-headed Whale, Peponocephala electra
      - Genus Orcinus
      -
- Orca (Killer Whale), Orcinus orca
      - Genus Feresa
      -
- Pygmy Killer Whale, Feresa attenuata
      - Genus Pseudorca
      -
- False Killer Whale, Pseudorca crassidens
      - Genus Globicephala
      -
- Long-finned Pilot Whale, Globicephala melas
      -
- Short-finned Pilot Whale, Globicephala macrorhynchus
      - Genus Delphinus
      -
- Long-beaked Common Dolphin, Delphinus capensis
      -
- Short-beaked Common Dolphin, Delphinus delphis
      - Genus Lissodelphis
      -
- Northern Rightwhale Dolphin, Lissodelphis borealis
      -
- Southern Rightwhale Dolphin, Lissodelphis peronii
      - Genus Sotalia
      -
- Tucuxi, Sotalia fluviatilis
      - Genus Sousa
      -
- Pacific Humpback Dolphin, Sousa chinensis
      -
- Indian Humpback Dolphin, Sousa plumbea
      -
- Atlantic Humpback Dolphin, Sousa teuszii
      - Genus Stenella
      -
- Atlantic Spotted Dolphin, Stenella frontalis
      -
- Clymene Dolphin, Stenella clymene
      -
- Pantropical Spotted Dolphin, Stenella attenuata
      -
- Spinner Dolphin, Stenella longirostris
      -
- Striped Dolphin, Stenella coeruleoalba
      - Genus Steno
      -
- Rough-toothed Dolphin, Steno bredanensis
      - Genus Tursiops
      -
- Common Bottlenose Dolphin, Tursiops truncatus
      -
- Indo-Pacific Bottlenose Dolphin, Tursiops aduncus
      - Genus Cephalorhynchus
      -
- Chilean Dolphin, Cephalorhynchus eutropia
      -
- Commerson's Dolphin, Cephalorhynchus commersonii
      -
- Heaviside's Dolphin, Cephalorhynchus heavisidii
      -
- Hector's Dolphin, Cephalorhynchus hectori
      - Genus Grampus
      -
- Risso's Dolphin, Grampus griseus
      - Genus Lagenodelphis
      -
- Fraser's Dolphin, Lagenodelphis hosei
      - Genus Lagenorhynchus
      -
- Atlantic White-sided Dolphin, Lagenorhynchus acutus
      -
- Dusky Dolphin, Lagenorhynchus obscurus
      -
- Hourglass Dolphin, Lagenorhynchus cruciger
      -
- Pacific White-sided Dolphin, Lagenorhynchus obliquidens
      -
- Peale's Dolphin, Lagenorhynchus australis
      -
- White-beaked Dolphin, Lagenorhynchus albirostris
      - Genus Orcaella
      -
- Irrawaddy Dolphin, Orcaella brevirostris
      -
- Australian Snubfin Dolphin, Orcaella heinsohni
    - Family Phocoenidae: porpoises
    - Family Monodontidae: Beluga and Narwhal
    - Family Physeteridae: Sperm Whale
    - Family Kogiidae: Pygmy Sperm Whale and Dwarf Sperm Whale
    - Family Ziphiidae: beaked whales Category:Cetaceans

Platanistoidea

See text River dolphins are four species of dolphin which reside in freshwater rivers and estuaries. They are classed in the Platanistoidea superfamily of cetaceans. Three species live in fresh water rivers. The fourth species, the La Plata Dolphin, lives in saltwater estuaries and the ocean. However it is scientifically classed in the river dolphin family rather than the oceanic dolphin family.

Ecology

River dolphins are some of the most endangered of all the world's cetaceans. Due to habitat loss, hunting by humans, and naturally low numbers, they are extremely vulnerable to extinction. Also, many river dolphins also possess very poor eyesight — some are considered blind — which can lead to unfortunate encounters with humans or manmade objects (boats or fishing nets for example). Some dolphin species can live in marine or riverine environments. The Tucuxi, for example, is equally at home in both ecotypes. However these are not classified in the Platanistoidea superfamily and are therefore not regarded as true river dolphins.

Taxonomy

In the most recent classification (Rice, 1998) there are four families that make up the river dolphins. Platanistidae is listed as the only extant family of the Platanistoidea superfamily. The previously accepted classification treated all four families as belonging to this superfamily and treated the Ganges and Indus River Dolphins as separate species.

Classification by Rice (1998)


- Superfamily Platanistoidea
  - Family Platanistidae
    - Ganges and Indus River Dolphin Platanista gangetica
  - Family Iniidae
    - Amazon River Dolphin (or Boto) Inia geoffrensis
  - Family Lipotidae
    - Chinese River Dolphin (or Baiji) Lipotes vexillifer
  - Family Pontoporiidae
    - La Plata Dolphin (or Franciscana) Pontoporia blainvillei

Previous classification


- Superfamily Platanistoidea
  - Family Platanistidae
    - Ganges River Dolphin Platanista gangetia
    - Indus River Dolphin Platanista minor
  - Family Iniidae
    - Amazon River Dolphin (or Boto) Inia geoffrensis
  - Family Lipotidae
    - Chinese River Dolphin (or Baiji) Lipotes vexillifer
  - Family Pontoporiidae
    - La Plata Dolphin (or Franciscana) Pontoporia blainvillei

References


- Rice, Dale W. (1998). Marine mammals of the world: systematics and distribution. Society of Marine Mammalogy Special Publication Number 4. 231 pp. Category:Cetaceans

Bottlenose Dolphin

The Bottlenose Dolphin (Tursiops truncatus) is the most common and well-known dolphin species. It inhabits warm and temperate seas worldwide and may be found in all but the Arctic and the Antarctic Oceans.

Physical description

Bottlenose Dolphins are grey, varying from dark grey at the top near the dorsal fin to very light grey and almost white at the underside. This makes them hard to see both from above and below when swimming. The elongated upper and lower jaws give the animals their name of bottlenose. The real nose however is the blowhole on top of the head. Their face shows a characteristic "smile". Adults range in length from 2 to 4m (6 to 13 feet) and in weight from 150 to 650kg (330 to 1430 pounds) with males being slightly longer and considerably heavier than females on average. The size of the dolphin appears to vary considerably with habitat. Most research in this area has been restricted to the North Atlantic Ocean, where researchers (Hersh & Duffield, 1990) have identified two ecotypes. Those dolphins in warmer, shallower waters tend to have a smaller body than their cousins in cooler pelagic waters. For example a survey of animals in the Moray Firth in Scotland, the world's northernmost resident population, recorded an average adult length of just under 4m (13 feet). This compares with a 2.5m (8 feet) average in a population off Florida. Those in colder waters also have a fattier composition and blood more suited to deep-diving. The flukes (lobes of the tail) and dorsal fin are formed of dense connective tissue and don't contain bones or muscle. The animal propels forward by moving the flukes up and down. The pectoral flippers (at the sides of the body) serve for steering; they contain bones clearly homologous to the forelimbs of land mammals (from which dolphins and all other cetaceans evolved some 50 million years ago).

Behavior and life

cetacea Bottlenose Dolphins typically swim at a speed of 5-11km per hour (3-6 miles per hour); for short times, they can reach peak speeds of 35km per hour (21 mph). Every 5-8 minutes, the dolphins have to rise to the surface to breathe through their blowhole. (On average, they breathe more often however, several times per minute.) Their sleep is thus very light; some scientists have suggested that the two halves of their brains take turns in sleeping and waking. Bottlenose Dolphins normally live in groups called pods, containing up to 12 animals. These are long-term social units. Typically, a group of females and their young live together in a pod, and juveniles in a mixed pod. Several of these pods can join together to form larger groups of one hundred dolphins or more. Males live mostly alone or in groups of 2-3 and join the pods for short periods of time. The species is commonly known for its friendly character and curiosity. It is not uncommon for a diver to be investigated by a group of them. Occasionally, dolphins have rescued an injured diver by raising them to the surface, a behaviour they also show towards injured members of their own species. In November 2004, a more dramatic report of dolphin intervention came from New Zealand. Three lifeguards, swimming 100m off the coast near Whangarei, were reportedly approached by a 3m Great White Shark. A group of Bottlenose Dolphins, apparently sensing danger to the swimmers, herded them together and tightly surrounded them for forty minutes, preventing an attack from the shark, as they returned to shore. (Thomson, 2004) Dolphins are predators however, and they also show aggressive behaviors. This includes fights among males for rank and access to females, as well as aggressions towards sharks and other smaller species of dolphins. Male dolphins, during the mating season, compete very vigorously with each other through showing toughness and size with a series of acts such as head butting. Female Bottlenose Dolphins live for about 40 years; the more stressful life of the males apparently takes its toll, and they rarely live more than 30 years.

Diet

Their diet consists mainly of small fish, occasionally also