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Dinosaurs are a diverse group of animals of the clade Dinosauria. They first appeared during the Triassic period, 231.4 million years ago, and were the dominant terrestrial vertebrates for 135 million years, from the beginning of the Jurassic (about 201 million years ago) until the end of the Cretaceous (66 million years ago), when the Cretaceous–Paleogene extinction event led to the extinction of most dinosaur groups at the close of the Mesozoic Era. The fossil record indicates that birds evolved from theropod dinosaurs during the Jurassic Period and, consequently, they are considered a subgroup of dinosaurs by many paleontologists. Some birds survived the extinction event that occurred 66 million years ago, and their descendants continue the dinosaur lineage to the present day.
Dinosaurs are a varied group of animals from taxonomic, morphological and ecological standpoints. Birds, at over 10,000 living species, are the most diverse group of vertebrates besides perciform fish. Using fossil evidence, paleontologists have identified over 500 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species and fossil remains. Some are herbivorous, others carnivorous. While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. Evidence suggests that egg laying and nest building are additional traits shared by all dinosaurs. While modern birds are generally small due to the constraints of flight, many prehistoric dinosaurs were large-bodied—the largest sauropod dinosaurs may have achieved lengths of 58 meters (190 feet) and heights of 9.25 meters (30 feet 4 inches). Still, the idea that non-avian dinosaurs were uniformly gigantic is a misconception based on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small: Xixianykus, for example, was only about 50 cm (20 in) long.
Although the word dinosaur means "terrible lizard", the name is somewhat misleading, as dinosaurs are not lizards. Instead, they represent a separate group of reptiles which, like many extinct forms, did not exhibit characteristics traditionally seen as reptilian, such as a sprawling limb posture or ectothermy. Additionally, many prehistoric animals, including mosasaurs, ichthyosaurs, pterosaurs, plesiosaurs, and Dimetrodon, are popularly conceived of as dinosaurs, but are not classified as dinosaurs. Through the first half of the 20th century, before birds were recognized to be dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction.
Since the first dinosaur fossils were recognized in the early 19th century, mounted fossil dinosaur skeletons have been major attractions at museums around the world, and dinosaurs have become an enduring part of world culture. The large sizes of some groups, as well as their seemingly monstrous and fantastic nature, have ensured dinosaurs' regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, and new discoveries are regularly covered by the media.
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Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species) but a form taxon, since swans and geese are not considered ducks. Ducks are mostly aquatic birds, mostly smaller than the swans and geese, and may be found in both fresh water and sea water.
Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules, and coots.
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Dung beetles are beetles that feed partly or exclusively on feces. All the species belong to the superfamily Scarabaeoidea; most of them to the subfamilies Scarabaeinae and Aphodiinae of the family Scarabaeidae (scarab beetles). As most species of Scarabaeinae feed exclusively on feces, that subfamily is often dubbed true dung beetles. There are dung-feeding beetles which belong to other families, such as the Geotrupidae (the earth-boring dung beetle). The Scarabaeinae alone comprises more than 5,000 species.
Many dung beetles, known as rollers, roll dung into round balls, which are used as a food source or brooding chambers. Other dung beetles, known as tunnelers, bury the dung wherever they find it. A third group, the dwellers, neither roll nor burrow: they simply live in manure. They are often attracted by the dung burrowing owls collect.
Dung beetles are currently the only insect known to navigate and orient themselves using the Milky Way.
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Earwigs make up the insect order Dermaptera, found throughout the Americas, Africa, Eurasia, Australia and New Zealand. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cerci, a pair of forceps pincers on their abdomen, and membranous wings folded underneath short forewings, hence the scientific order name, "skin wings." Some groups are tiny parasites on mammals and lack the typical pincers. Earwigs rarely use their flying ability.
Earwigs are nocturnal; they often hide in small, moist crevices during the day, and are active at night, feeding on a wide variety of insects and plants. Damage to foliage, flowers, and various crops is commonly blamed on earwigs, especially the common earwig Forficula auricularia.
Earwigs have five molts in the year before they become adults. Many earwig species display maternal care, which is uncommon among insects. Female earwigs may care for their eggs, and even after they have hatched as nymphs will continue to watch over offspring until their second molt. As the nymphs molt, sexual dimorphism such as differences in pincer shapes begins to show.
Some earwig specimen fossils are in the extinct suborders Archidermaptera or Eodermaptera, the former dating to the Late Triassic and the latter to the Middle Jurassic. Many orders of insect have been theorized to be closely related to earwigs, though the icebugs of Grylloblattaria are most likely.
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Elephant seals (also sea elephants) are large, oceangoing seals in the genus Mirounga. The 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 19th 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 most northerly breeding location on the Pacific Coast is at Race Rocks, at the southern tip of Vancouver Island in the Strait of Juan de Fuca. The southern elephant seal is found in the Southern Hemisphere on islands such as South Georgia and 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. Fossils of an as yet unnamed species of Mirounga have been found in South Africa, and dated to the Miocene epoch.
Elephant seals breed annually and are seemingly faithful to colonies that have been established breeding areas.
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Elephants are large mammals of the family Elephantidae and the order Proboscidea. Traditionally, two species are recognised, the African elephant (Loxodonta africana) and the Asian elephant (Elephas maximus), although some evidence suggests that African bush elephants and African forest elephants are separate species (L. africana and L. cyclotis respectively). Elephants are scattered throughout sub-Saharan Africa, South Asia, and Southeast Asia. Elephantidae are the only surviving family of the order proboscidea; other, now extinct, families of the order include mammoths and mastodons. The largest living terrestrial animals, male African elephants can reach a height of 4 m (13 ft) and weigh 7,000 kg (15,000 lb). All elephants have several distinctive features the most notable of which is a long proboscis or trunk used for many purposes, particularly for grasping objects. In addition to their trunks, their incisors grow into tusks, which serve as tools for moving objects and digging and as weapons for fighting. The elephant's large ear flaps help to control the temperature of its body. African elephants have larger ears and concave backs while Asian elephants have smaller ears and convex or level backs.
Elephants are herbivorous and can be found in different habitats including savannahs, forests, deserts and marshes. They prefer to stay near water. They are considered to be keystone species due to their impact on their environments. Other animals tend to keep their distance, and predators such as lions, tigers, hyenas and wild dogs usually target only the young elephants (or "calves"). Females ("cows") tend to live in family groups, which can consist of one female with her calves or several related females with offspring. The groups are led by an individual known as the matriarch, often the oldest cow. Elephants have a fission-fusion society in which multiple family groups come together to socialise. Males ("bulls") leave their family groups when they reach puberty, and may live alone or with other males. Adult bulls mostly interact with family groups when looking for a mate and enter a state of increased testosterone and aggression known as musth, which helps them gain dominance and reproductive success. Calves are the centre of attention in their family groups and rely on their mothers for as long as three years. Elephants can live up to 70 years in the wild. They communicate by touch, sight, smell and sound; elephants use infrasound, and seismic communication over long distances. Elephant intelligence has been compared with that of primates and cetaceans. They appear to have self-awareness and show empathy for dying or dead individuals of their kind.
African elephants are listed as vulnerable by the International Union for Conservation of Nature (IUCN), while the Asian elephant is classed as endangered. One of the biggest threats to elephant populations is the ivory trade, as the animals are poached for their ivory tusks. Other threats to wild elephants include habitat destruction and conflicts with local people. Elephants are used as working animals in Asia. In the past they were used in war; today, they are often put on display in zoos and circuses. Elephants are highly recognisable and have been featured in art, folklore, religion, literature and popular culture.
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Esox is a genus of freshwater fish, the only living genus in the family Esocidae—the esocids which were endemic to North America, Europe and Eurasia during the Paleogene through present.
The type species is E. lucius, the northern pike. The species of this genus are known as pike and pickerel, and in heraldry they are usually called lucy.
The big pike species are native to the Palearctic and Nearctic ecozones, ranging across northern North America and from Western Europe to Siberia in Eurasia.
Pikes have the elongated, torpedo-like form of predatory fishes, with sharply-pointed heads and sharp teeth. Their coloration is typically grey-green with a mottled or spotted appearance with stripes along their back, perfectly camouflaged among weeds. Individual pike marking patterns are unique, like fingerprints. Pike can grow to a maximum recorded length of 1.83 metres (6 ft 0 in), reaching a maximum recorded weight of 35 kilograms (77 lb). There are currently six recognized species in this genus: There is one fossil species, Esox kronneri Grande, 1999 known from the Eocene of the Green River formation.
The generic name Esox (pike fish) derives from the Greek ίσοξ (a kind of fish), itself a word of Celtic origin related to the Welsh eog and Irish Gaelic iasc (fish). Pliny uses the Latin form esox in reference to a large fish in the Rhine normally identified with lax (salmon). It is likely that Carolus Linnaeus's application of Esox to the pike is thus a misnomer.
The English common name "pike" is an apparent shortening of "pike-fish", in reference to its pointed head, Old English píc originally referring to a pickaxe. The plural of pike is pike.
A northern English and Lowland Scots name for the pike, ged, similarly derives from Old Norse gaddr (spike) (cf. the modern Swedish name for the pike, gädda, the Danish "gedde", the Norwegian "gjedde" and Scottish Gaelic: geadais). The Dutch name for the pike (snoek) has been given to a wide variety of fish reminding sailors of the pike (see snoek, snook).
The English "pike" originally referred specifically to the adult fish, the diminutive form "pickerel" (now used to name some of the smaller pike, E. americanus and E. niger) referring to the young. The walleye (Sander vitreus) is sometimes called a pickerel by Gerard, but it is unrelated to the pike, being a member of the perch family (family Percidae). Pike are not to be confused with the unrelated pikeminnows (traditionally, and perhaps better, known as squawfish) of genus Ptychocheilus (family Cyprinidae) or pikeperch (Sander lucioperca) which is more akin to walleye than to pike. Pike are also called "Jackfish" in North America and informally "Slough Shark" in Western Canada.
Pike feed on a wide range of food sources, predominantly smaller shoal fish. Pike are also cannibalistic, sometimes preying upon smaller members of their own species.
They will also prey on insects and amphibians such as newts or frogs in times when their usual food is scarce, and occasionally on small mammals like moles or mice when caught water-borne. Small birds such as ducklings may become a target for hungry pike. Pike are also known to prey on swimming snakes.
They are, however, undeserving of their reputation for being overly vicious predators. There are few substantiated incidents of pike 'attacks' on people. Pike's further reputation as a pest seems to lie predominately amongst anglers who seek more desirable species.
Effective methods for catching this hard-fighting fish include dead baits, live baits, and lure fishing. Pike can easily be damaged when handled since they are not as robust as their reputation would suggest. Colour of lure can be influenced by water clarity and weather conditions. Since pike have numerous sharp teeth it is wise to take extreme care when unhooking them. The use of a wet leather gauntlet and surgical forceps to remove hooks is highly recommended on safety grounds. If practising catch and release fishing, care for the pike should be the pike angler's utmost concern. The formerly recommended practice of grasping a pike by its eye sockets (tragically interpreted as "its eyes") resulted in countless released pike that quickly died from inability to see prey any longer.
The current recommended method of grasping pike is to close the hand firmly over the gill covers, and to make the period of handling as short as possible before release. Grabbing a pike by the gill covers is not feasible when a pike is very big, but it is easy to handle a pike by inserting the fingers at the bottom of the gill opening and grabbing the lower jaw. Big pike should also be supported at the belly. When a pike is held this way it is also easier to keep the mouth open to remove a hook. Many anglers now use special grips to grab the pike's front lower jaw, which can add to the safety of an anglers because of the danger imposed by the hooks of the lure or tackle and the pike's teeth. The Pike Anglers Club was formed in 1977 to campaign for the preservation of pike and the sport of pike fishing.
A practice known as gut hooking was previously widely used in catching pike. Upon taking the bait, the pike will hold it for a short time in its mouth as it moves off. The pike will then, usually, turn the bait in its mouth, so that it sits in alignment with its throat to ease swallowing. It is recommended that when pike fishing the process is not allowed to go this far and a strike is recommended as soon as a bite is indicated. Otherwise, what is known as gut hooking will result, which will normally kill or seriously injure the fish. Dutch research shows that cutting the line immediately when the fish is gut hooked will still give low mortality (14%). The hooks in the gut or stomach were either encapsulated or removed from the body. Placing hooks near the rear of the bait reduces the risk of deep hooking. Other methods of catching and handing pike that are now frowned upon are the gaff and the gag. The gaff is a metal hook on the end of a pole used to hook through the fish's body in place of a more humane landing net. A gag is a device for holding open the pike's mouth whilst unhooking. These are now illegal in Scotland, as they put a huge amount of pressure on a pike's jaw, thus causing irreparable damage.
Russian mythology holds that the pike is one of several forms assumed by evil water spirits called vodyanoy, and a ravenous mythical pike is traditionally blamed for decimating the fish population in the Sheksna River. Russian fairy tales, on the other hand, also tell about an old wise pike that can fulfil wishes of the one who catches it, if its catcher releases it back into its habitat. In the Finnish Kalevala, Väinämöinen creates a kantele (string instrument) from the jawbone of the pike.
Two United States Navy submarines have been named Pike, SS-6 of 1903 and SS-173 of 1935, and three, SS-22 of 1912, SS-177 of 1936, and SS-524 of 1944, named Pickerel. In addition, the Soviet submarines known to NATO as the Victor III class were called the Shchuka (Щука, "pike") class, in Russian. The Soviet Iosif Stalin tank (IS-3) was also nicknamed Shchuka, in reference to its sharply pointed hull front.
In heraldry, the pike is called a lucy. It is usually blazoned either naiant (swimming), embowed (bowed) or hauriant (jumping), though pairs of lucies may appear addorsed (back to back), as in the arms of the Finnish town of Uusikaupunki, Finland. (Argent, two lucies addorsed azure).
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Exocoetidae is a family of marine fish in the order Beloniformes of class Actinopterygii. Fish of this family are known as flying fish. There are about sixty-four species grouped in seven to nine genera. Flying fish can make powerful, self-propelled leaps out of water into air, where their long, wing-like fins enable gliding flight for considerable distances above the water's surface. This uncommon ability is a natural defense mechanism to evade predators.
The oldest known fossil of a flying or gliding fish, Potanichthys xingyiensis, dates back to the Middle Triassic, 235–242 million years ago. However, this fossil is not related to modern flying fish, which evolved independently about 65 million years ago.
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Fleas are the insects forming the order Siphonaptera. They are wingless, with mouthparts adapted for piercing skin and sucking blood. Fleas are external parasites, living by hematophagy off the blood of mammals and birds.
Some flea species include:Over 2,000 species have been described worldwide.
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Fox is a common name for many species of alert omnivorous mammals belonging to the Canidae family. Foxes are small-to-medium-size canids (slightly smaller than a medium-size domestic dog), with a flattened skull, upright triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or brush).
Members of about 37 species are referred to as foxes, of which only 12 species actually belong to the Vulpes genus of "true foxes". By far the most common and widespread species of fox is the red fox (Vulpes vulpes), although various species are found on almost every continent. The presence of fox-like carnivores all over the globe, together with their widespread reputation for cunning, has contributed to their appearance in popular culture and folklore in many societies around the world (see also Foxes in culture). The hunting of foxes with packs of hounds, long an established pursuit in Europe, especially the British Isles, was exported by European settlers to various parts of the New World.
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