Mating-20

熊猫！！（英语）

Humpback Whale

The Humpback Whale (Megaptera novaeangliae) is a baleen whale. One of the larger rorqual species, adults range in length from 12–16 metres (40–50 ft) and weigh approximately 36,000 kilograms (79,000 lb). The Humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water. Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time. The purpose of the song is not yet clear, although it appears to have a role in mating.。

Found in oceans and seas around the world, Humpback Whales typically migrate up to 25,000 kilometres each year. Humpbacks feed only in summer, in polar waters, and migrate to tropical or sub-tropical waters to breed and give birth in the winter. During the winter, Humpbacks fast and live off their fat reserves. The species' diet consists mostly of krill and small fish. Humpbacks have a diverse repertoire of feeding methods, including the spectacular bubble net fishing technique.。

Like other large whales, the Humpback was and is a target for the whaling industry. Due to over-hunting its population fell by an estimated 90% before a whaling moratorium was introduced in 1966. Stocks of the species have since partially recovered, however entanglement in fishing gear, collisions with ships, and noise pollution also remain concerns. There are at least 70,000 humpback whales worldwide. Once hunted to the brink of extinction, Humpbacks are now sought out by whale-watchers, particularly off parts of Australia and the United States. On November 18, 2007 a Japanese fleet set off for the first time in decades to hunt the humpback in the South Pacific[2].。

Humpback Whales are rorquals (family Balaenopteridae), a family that includes the Blue Whale, the Fin Whale, the Bryde's Whale, the Sei Whale and the Minke Whale. The rorquals are believed to have diverged from the other families of the suborder Mysticeti as long ago as the middle Miocene.[3] However, it is not known when the members of these families diverged from each other.。

Though clearly related to the giant whales of the genus Balaenoptera, the Humpback has been the sole member of its genus since Gray's work in 1846. More recently though, DNA sequencing analysis has indicated both the Humpback and the Gray Whale are close relatives of the Blue Whale, the world's largest animal. If further research confirms these relationships, it will be necessary to reclassify the rorquals.。

The Humpback Whale was first identified as "baleine de la Nouvelle Angleterre" by Mathurin Jacques Brisson in his Regnum Animale of 1756. In 1781, Georg Heinrich Borowski described the species, converting Brisson's name to its Latin equivalent, Balaena novaeangliae. Early in the 19th century Lacépède shifted the Humpback from the Balaenidae family, renaming it Balaenoptera jubartes. In 1846, John Edward Gray created the genus Megaptera, classifying the Humpback as Megaptera longpinna, but in 1932, Remington Kellogg reverted the species names to use Borowski's novaeangliae.[4] The common name is derived from their humping motion while swimming. The generic name Megaptera from the Greek mega-/μεγα- "giant" and ptera/πτερα "wing",[5] refers to their large front flippers. The specific name means "New Englander" and was probably given by Brisson due the regular sightings of Humpbacks off the coast of New England.[4]。

Humpback Whales can easily be identified by their stocky bodies with obvious humps and black dorsal colouring. The head and lower jaw are covered with knobs called tubercles, which are actually hair follicles and are characteristic of the species. The tail flukes, which are lifted high in the dive sequence, have wavy rear edges.[6]。

The long black and white tail fin, which can be up to a third of body length, and the pectoral fins have unique patterns, which enable individual whales to be recognised.[7][8] Several suggestions have been made to explain the evolution of the Humpback's pectoral fins, which are proportionally the longest fins of any cetacean. The two most enduring hypotheses are the higher maneuverability afforded by long fins, or that the increased surface area is useful for temperature control when migrating between warm and cold climates.。

Humpbacks have 270 to 400 darkly coloured baleen plates on each side of the mouth. Ventral grooves run from the lower jaw to the umbilicus about halfway along the bottom of the whale. These grooves are less numerous (usually 16–20) and consequently more prominent than in other rorquals. The stubby dorsal fin is visible soon after the blow when the whale surfaces, but has disappeared by the time the flukes emerge. Humpbacks have a distinctive 3 m (10 ft) bushy blow.。

Newborn calves are roughly the length of their mother's head. A 50' mother would have a 20' newborn weighing in at 2 tons! They are nursed by their mothers for approximately six months, then are sustained through a mixture of nursing and independent feeding for possibly six months more. Some calves have been observed alone after arrival in Alaskan waters. Females reach sexual maturity at the age of five with full adult size being achieved a little later. According to new research, males reach sexual maturity at approximately 7 years of age. Fully grown the males average 15–16 m (49–52 ft), the females being slightly larger at 16–17 m (52–56 ft), with a weight of 40,000 kg (or 44 tons); the largest recorded specimen was 19 m (62 ft) long and had pectoral fins measuring 6 m (20 ft) each.[9] The largest Humpback on record, according to whaling records, was killed in the Caribbean. She was 88 feet long, weighing nearly 90 tons!。

Females have a hemispherical lobe about 15 centimetres (6 in) in diameter in their genital region. This allows males and females to be distinguished if the underside of the whale can be seen, even though the male's penis usually remains unseen in the genital slit. Male whales have distinctive scars on heads and bodies, some resulting from battles over females.。

Females typically breed every two or three years. The gestation period is 11.5 months, yet some individuals can breed in two consecutive years. Humpback Whales were thought to live 50 - 60 years, but new studies using the changes in amino acids behind eye lenses proved another baleen whale, the Bowhead, to be 211 years old. This was an animal taken by the Inuit off Alaska. More studies on ages are currently being done.。

The varying patterns on the Humpback's tail flukes are sufficient to identify an individual. Unique visual identification is not possible in most cetacean species (exceptions include Orcas and Right Whales), so the Humpback has become one of the most-studied species. A study using data from 1973 to 1998 on whales in the North Atlantic gave researchers detailed information on gestation times, growth rates, and calving periods, as well as allowing more accurate population predictions by simulating the mark-release-recapture technique. A photographic catalogue of all known whales in the North Atlantic was developed over this period and is currently maintained by Wheelock College.[10] Similar photographic identification projects have subsequently begun in the North Pacific by SPLASH (Structure of Populations, Levels of Abundance and Status of Humpbacks), and around the world.。

Social structure and courtship：

Humpbacks frequently breach, throwing two thirds or more of their body out of the water and splashing down on their back.。

Humpbacks frequently breach, throwing two thirds or more of their body out of the water and splashing down on their back.。

The Humpback social structure is loose-knit. Usually, individuals live alone or in small transient groups that assemble and break up over the course of a few hours. Groups may stay together a little longer in summer in order to forage and feed cooperatively. Longer-term relationships between pairs or small groups, lasting months or even years, have been observed, but are rare. Recent studies extrapolate feeding bonds observed with many females in Alaskan waters over the last 10 years. It is possible some females may have these bonds for a lifetime. More studies need to be done on this. The range of the Humpback overlaps considerably with many other whale and dolphin species — whilst it may be seen near other species (for instance, the Minke Whale), it rarely interacts socially with them. Humpback calves have been observed in Hawaiian waters playing with bottlenose dolphin calves.。

Courtship rituals take place during the winter months, when the whales migrate towards the equator from their summer feeding grounds closer to the poles. Competition for a mate is usually fierce, and female whales as well as mother-calf dyads are frequently trailed by unrelated male whales dubbed escorts by researcher Louis Herman. Groups of two to twenty males typically gather around a single female and exhibit a variety of behaviours in order to establish dominance in what is known as a competitive pod. The displays may last several hours, the group size may ebb and flow as unsuccessful males retreat and others arrive to try their luck. Techniques used include breaching, spy-hopping, lob-tailing, tail-slapping, flipper-slapping, charging and parrying. "Super pods" have been observed numbering more than 40 males, all vying for the same female. (M. Ferrari et. al)。

Whale song is assumed to have an important role in mate selection; however, scientists remain unsure whether the song is used between males in order to establish identity and dominance, between a male and a female as a mating call, or a mixture of the two. All these vocal and physical techniques have also been observed while not in the presence of potential mates. This indicates that they are probably important as a more general communication tool. Recent studies showed singing males attract other males. Scientists are extrapolating possibilities the singing may be a way to keep the migrating populations connected. (Ferrari, Nicklin, Darling, et. al.) Studies on this are ongoing.。

Feeding：

A group of 15 whales bubble net fishing near Juneau, Alaska。

A group of 15 whales bubble net fishing near Juneau, Alaska。

The species feeds only in summer and lives off fat reserves during winter. Humpback Whales will only feed rarely and opportunistically while in their wintering waters. It is an energetic feeder, taking krill and small schooling fish, such as herring (Clupea harengus), salmon, capelin (Mallotus villosus) and sand lance (Ammodytes americanus) as well as Mackerel (Scomber scombrus), pollock (Pollachius virens) and haddock (Melanogrammus aeglefinus) in the North Atlantic.[11][12][13] Krill and Copepods have been recorded from Australian and Antarctic waters.[14] It hunts fish by direct attack or by stunning them by hitting the water with its flippers or flukes.。

A pair of Humpback Whales feeding by lunging.。

A pair of Humpback Whales feeding by lunging.。

The Humpback has the most diverse repertoire of feeding methods of all baleen whales.[15] Its most inventive technique is known as bubble net fishing: a group of whales blows bubbles while swimming in circles to create a ring of bubbles. The ring encircles the fish, which are confined in an ever-tighter area as the whales swim in a smaller and smaller circles. The whales then suddenly swim upwards through the bubble net, mouths agape, swallowing thousands of fish in one gulp. This technique can involve a ring of bubbles up to 30 m (100 ft) in diameter and the cooperation of a dozen animals. Some of the whales take the task of blowing the bubbles through their blowholes, some dive deeper to drive fish towards the surface, and others herd fish into the net by vocalizing. It is one of the more spectacular acts of collaboration among marine mammals.[16]。

Humpback Whales are preyed upon by Orcas. The result of these attacks is generally nothing more serious than some scarring of the skin, but it is likely that young calves are sometimes killed.[17]。

Song：

Both male and female Humpback Whales can produce sounds, however only the males produce the long, loud, complex "songs" for which the species is famous. Each song consists of several sounds in a low register that vary in amplitude and frequency, and typically lasts from 10 to 20 minutes.[18] Songs may be repeated continuously for several hours; Humpback Whales have been observed to sing continuously for more than 24 hours at a time. As cetaceans have no vocal cords, whales generate their song by forcing air through their massive nasal cavities.。

Whales within an area sing the same song, for example all of the Humpback Whales of the North Atlantic sing the same song, and those of the North Pacific sing a different song. Each population's song changes slowly over a period of years —never returning to the same sequence of notes.[18]。

Scientists are still unsure of the purpose of whale song. Only male Humpbacks sing, so it was initially assumed that the purpose of the songs was to attract females. However, many of the whales observed to approach singing whales have been other males, with the meeting resulting in a conflict. Thus, one interpretation is that the whale songs serve as a threat to other males.[19] Some scientists have hypothesized that the song may serve an echolocative function.[20] During the feeding season, Humpback Whales make altogether different vocalizations, which they use to herd fish into their bubble nets.[21]。

Population and distribution：

The Humpback whale is found in all the major oceans, in a wide band running from the Antarctic ice edge to 65° N latitude, though is not found in the eastern Mediterranean, the Baltic Sea or the Arctic Ocean. There are at least over 70,000 humpback whales worldwide, with 10,000-25,000 in the North Pacific, nearly 12,000 in the North Atlantic, and over 50,000 in the Southern Hemisphere, down from a pre-whaling population of 125,000[citation needed].。

The Humpback is a migratory species, spending its summers in cooler, high-latitude waters, but mating and calving in tropical and sub-tropical waters.[18] An exception to this rule is a population in the Arabian Sea, which remains in these tropical waters year-round.[18] Annual migrations of up to 25,000 kilometres (16,000 statute miles) are typical, making it one of the farthest-travelling of any mammalian species.。

A 2007 study identified seven individual whales wintering off the Pacific coast of Costa Rica as those which had made a trip from the Antarctic of around 8,300 km. Identified by their unique tail patterns, these animals have made the longest documented migration by a mammal.[22]。

In Australia, two main migratory populations have been identified, off the west and east coast respectively. These two populations are distinct with only a few females in each generation crossing between the two groups.[23]。

Whaling：

One of the first attempts to hunt the humpback whale was made by John Smith in 1614 off the coast of Maine. Opportunistic killing of the species is likely to have occurred long before, and it continued with increasing pace in the following centuries. By the 18th century, the commercial value of Humpback Whales had been recognized[citation needed], and they became a common target for whalers for many years.。

By the 19th century, many nations (and the United States in particular), were hunting the animal heavily in the Atlantic Ocean — and to a lesser extent in the Indian and Pacific Oceans. However, it was the introduction of the explosive harpoon in the late 19th century that allowed whalers to accelerate their take. This, coupled with the opening-up of the Antarctic seas in 1904, led to a sharp decline in all whale populations.。

It is estimated that during the 20th century at least 200,000 Humpbacks were taken, reducing the global population by over 90%, with the population in the North Atlantic estimated to have dropped to as low as 700 individuals.[24] To prevent species extinction, a general moratorium on the hunting of Humpbacks was introduced in 1966 and is still in force today. In his book Humpback Whales (1996), Phil Clapham, a scientist at the Smithsonian Institute, said "This wanton destruction of some of the earth's most magnificent creatures [is] one of the greatest of our many environmental crimes."。

By the time the International Whaling Commission (IWC) members agreed on a moratorium on Humpback hunting in 1966, the whales were so scarce that commercial hunting was no longer worthwhile. At this time, 250,000 were recorded killed. However, the true toll is likely to be significantly higher. It is now known that the Soviet Union was deliberately under-recording its kills; the total Soviet Humpback kill was reported at 2,820 whereas the true number is now believed to be over 48,000.[25]。

As of 2004, hunting of Humpback Whales is restricted to a few animals each year off the Caribbean island Bequia in the nation of St. Vincent and the Grenadines.[15] The take is not believed to threaten the local population.。

Conservation:

Internationally this species is considered vulnerable. Most monitored stocks of Humpback Whales have rebounded well since the end of the commercial whaling era,[1] such as the North Atlantic where stocks are now believed to be approaching pre-hunting levels.[29] However, the species is considered endangered in some countries where local populations have recovered slowly, including the United States.[30]。

Today, individuals are vulnerable to collisions with ships, entanglement in fishing gear, and noise pollution.[1] Like other cetaceans, Humpbacks are sensitive to noise and can even be injured by it. In the 19th century, two Humpback Whales were found dead near sites of repeated oceanic sub-bottom blasting, with traumatic injuries and fractures in the ears.[31]。

The ingestion of saxitoxin, a PSP (paralytic shellfish poison) from contaminated mackerel has been implicated in Humpback Whale deaths.[32]。

Some countries are creating action plans to protect the Humpback; for example, in the United Kingdom, the Humpback Whale has been designated as a priority species under the national Biodiversity Action Plan, generating a set of actions to conserve the species. The sanctuary provided by National Parks such as Glacier Bay National Park and Preserve and Cape Hatteras National Seashore, among others, have also become a major factor in sustaining the populations of the species in those areas.[33]。

Although much was known about the Humpback Whale due to information obtained through whaling, the migratory patterns and social interactions of the species were not well known until two separate studies by R. Chittleborough and W. H. Dawbin in the 1960s.[34] Roger Payne and Scott McVay made further studies of the species in 1971.[35] Their analysis of whale song led to worldwide media interest in the species, and left an impression in the public mind that whales were a highly intelligent cetacean species, a contributing factor to the anti-whaling stance of many countries.。

牛怎样交配? - 百度百科

Name

Scientific name: Ailuiopodidae melanoleuca 。

Alias: Hua Hua Xiong Xiong Takekuma Silver Bear spent the first big raccoon dog-Mrs E Gasi bailiffs hole Leopard Meng Meng Yi Mo's Fresh beast tapir iron beast Pandas 。

English: Giant Panda 。

Categories

Carnivores (Carnivora) Bear Branch (Ursidae) panda subfamily (Ailurinae) 。

Endangered information 。

CITES: Appendix I 。

IUCN: Endangered 。

State protection levels: level 。

China's Red Book of endangered animals grading: Endangered 。

Shape Features 。

Giant panda Xiong body肥硕like, but the short end of the first round, his head and body coat color black and white clear. 。

Distribution

Only the upper reaches of the Yangtze River to China's Qinghai-Tibet Plateau deep alpine transition zone, including Qinling, Minshan, Qionglai Mountain, size and the size of Liangshan, etc. Ridge Mountains. Located in the south of the Qinling Mountains, is distributed mainly in Foping County, the general distribution of the Yangxian County, only a small amount of the distribution of county Taibai, Ningshan, weeks, etc.. Minshan of Gansu County, except for general distribution, the remaining are located in Sichuan. Sichuan mainly distributed in the county in Pingwu, Sichuan and Green Beichuan three counties, the general distribution of a Nanping, Songpan, Mau Timor, and other counties, a small amount of the distribution of county County, Mianzhu, Peng County, Shifang, and Dujiangyan City. Qionglai mountains are mainly distributed in Baoxing County, Wenchuan and Tianquan, a general distribution of Dayi and Lushan County, the only county with a small amount of Qionglai,崇庆, Kangding, Luding, etc.. Size of Mill Hongya and except for general distribution Mianning County, only a small amount of the distribution of Yingjing County, asbestos, Hanyuan, Kowloon. Size Liangshan addition Mabian, Meigu and the West have a certain number, only a small number of counties have甘洛, Ebian and Leibo, etc. (Pan Shi, 1988; Malaysian Yao, 1988; HU Jin-chu, 1985 ). Giant panda habitat and migratory habits of the mountains upstream of the Yangtze River deep mountains for the southeast monsoon wind surface, climate温凉humid, humidity often more than 80 percent, so they are a - hi moist animals. Their activities in the regional multi-Au ditch,山腹depression, valley terraces, usually in the 20 ° below the gentle slope terrain. These local soil hypertrophy, forest Maunsell, niitakayamensis grew well constitute a relatively stable temperature, good concealment conditions, food and water resources are abundant good food base. 。

Life Habits

In addition to estrus, often live alone Migratory life, and day and night trip. Nest domain area of 3.9-6.4 km2 volatile, and individual overlapping jurisdiction between the phenomenon of the nest, the nest of male domain slightly larger than female. Estrogen-only activities most of the time in 30 to 40 hectares of nuclear area, the female bodies in the nuclear domain do not overlap (HU Jin-chu, 1985). Food is the main mountain, subalpine about 50 kinds of bamboo, and even potable other plants, and even animal carcasses. Japanese appetite great day went to the drinking water springs or streams. Sexual maturity is 6.5-7.5, more than April estrus. In general was early September in the old trees in the farrowing nest hole, each child prolific 1 Aberdeen, occasionally producing 2 Aberdeen. With the baby after the mother left the mother of 18 months. The wild male and female sex ratio is about 1:1 (beam齐慧, 1993; Wen Wei Fu, 1994). 。

To risk factors 。

1, forest harvesting. Giant panda habitat area to the annual harvest of at least 10,000 hectares. Each of their habitat to about 2.5 km2 at the rate of disappearance (Kleiman et al, 1991). Nearly 30 years ago, Shaanxi, Gansu, and Sichuan Provinces distribution panda population in the area doubled to over 43 million people, large-scale logging enterprises since 1950-1985, a total of 27 (excluding县属logging Field), the harvesting of forest area to verify for more than 420,000 hectares, with an average annual logging area of over 20,000 hectares, resulting in habitat by the early 1970's 31,450 km2, and after 15 years, has dropped to 13921.52 km2 and reduce area of 17528.48 km2, accounting for the original habitat the 56 percent and caused six cutting the district Panda disappeared, 10 cutting the region only a handful of surviving panda, the sharp decline in population size (HU Jin-chu, 1993); 。

2, capturing too much. As in Wenchuan County grassland before liberation, Britain, the United States and other Western countries, then catch vivo acquisition of over 20 only (those killed outside), where the giant panda population which, to date more than 50 years, the number remains low, yet to return. Again宝兴县from 1963 to date, only one county to capture pandas reached 113 and above. From the mid-1950s, the giant pandas from the wild catch has been over 240 to display at home and abroad, which is concentrated in Baoxing 110 MS only, Ping Wu, more than 60 only, resulting in the two county population structure was damaged, a significant number of decreased (HU Jin-chu, 1993). According panda life table analysis, which a generation would take about 12 years, population growth is slow, such as large catch, even in the protection of a good situation, also take decades to restore; 。

3, and in recent years, the giant panda poaching smuggling hides were still occur from time to time; 。

4, the giant panda population distribution in more than 25 island isolated habitats. These isolated habitat area the size of 205 km2 (30-2384km range), the majority of whom (67%) of the area less than 350 km2 (Kleiman et al, 1991). This population of isolation and division is a long-term threat to its population of important factors, small groups of inbred recession phenomenon will reduce fecundity, larval survival and disease resistance. Ultimately "island" members will disappear. According to Pan, and others (1988) on the Qinling panda population genetic analysis, there are more than 200 giant pandas, can constitute a about 90 breeding groups, their generation hybrid rate decline rate was 0.54%, after 12 and after 140 years later, every member will have 1 / 8 of the same gene, or table (Church) brothers and sisters of the relationship; 。

5, due to human activities extend the scope of the giant pandas were forced to retreat to the Peak, a very simple bamboo species meet with a bamboo flowering, no room to maneuver, only 1975 Minshan region niitakayamensis flowering, the death of 138 over 1980's Qionglai Hill flowering cold niitakayamensis large area, the giant pandas disaster found the bodies 108, died 33 for a total 141 (HU Jin-chu, 1993); 。

6, in panda habitats exist without permission from the government of mineral development, pollution and the miners, tree felling and hunting is one of the threat (Kleiman et al, 1991). 。

Natural history 。

Giant panda is a unique black and white coat color with the lively animals. Its Latin name: Ailuropodamelanoleuca, it refers to the black and white appearance. The giant panda species is a controversial issue of a century: whether it belongs to Bear Branch, or as close as the Red Panda raccoon Branch, or a separate species? Recent DNA analysis indicates that giant pandas belonging to Bear Branch, a representative of the early Bear Branch branch. Adult pandas about 120-190 cm and weighing 85 to 125 kilograms. Unique features include: large and flat molars, it's a developed carpal has become a "pseudo-thumb" is to adapt to fresh bamboo for the living. Bear with other six different categories, pandas and sun bears are not hibernating behavior. 。

Food Properties 。

Panda very special recipes, including the almost alpine region can be found in the various bamboo, the pandas also occasionally carnivorous (usually animal body). Panda unique characteristics of the food it was the local people called "Bamboo Bear." Bamboo lack of nutrition, survival can only provide the basic nutritional requirements, the pandas adapt to a gradual evolution of the characteristics of this recipe. In the wild, in addition to sleep or short-range activities, daily feeding time for the giant pandas as long as 14 hours. A giant panda eating 12-38 kilograms of food per day, close to its body weight of 40%. Panda likes to eat bamboo most nutritious, containing cellulose least part of that Soft, shoots, and bamboo shoots. Giant panda habitat usually have at least two kinds of bamboo. When a bamboo flowering at the time of death (bamboo every 30-120 years will periodically flowering death), the giant pandas can turn feeding other bamboo. However, habitat fragmentation of the increased status within the habitat of bamboo may be only one, when such deaths bamboo, the pandas will be in the region face the threat of starvation. 。

Captive and social behavior 。

"Breeding difficulties" as news headlines to describe the propagation of the giant pandas situation. However, the study shows that although the wild giant pandas in captivity live longer state, but the wild, breeding success rate higher. In the wild, adult pandas regardless雄雌are involved in reproduction. Several female can fight duality and the male mating, but will be looking for a male in a different period of estrus females. In spring mating season 3-5 month, usually no more than 2-4 days. Pregnancy is about five months. Wild occasional twin circumstances, but generally only female panda feeding a cub. Captive populations, the twin of more. Before childbirth, female individuals find empty holes in tree roots and the production. Such shelters in the vicinity, and to stay on for three months, with its generous hand carefully care cub. Giant panda cub born very small, usually only 100-200 grams, there are only female bear the weight of 1 / 900. Panda cubs in the past few days to a month after the birth, the mother panda baby will be left in tree holes or holes out foraging. Mother beast sometimes leave two days or even longer. This does not mean that it abandoned baby, but the process of bringing up baby part of it is natural. Baby in the 12 months or so begun to eat bamboo, but in the meantime, they are completely dependent on his mother. Wild baby mortality rate lower than the pen, about 40 percent (Pan, and others, are being published). 。

Qinling region in the long-term study indicate that the giant panda breeding rate of about 0.654 baby / female / annual (Pan, and others, are produced), and North American natural population of brown bear some similar (Stringham1990). 。

Giant pandas are living animals, each adult domain clear of the nest, the male domain of individual nests are usually large, close to 30 square kilometers, general and the number of female individual nest domain overlap. When the nest male giant pandas in the same meet with each other jurisdictions, such as the estrus period of female pandas in the surrounding, and they have a clear hierarchy, will lead to an even struggle. The advantage of the individual male and female mating a priority, but there are also opportunities for other males. Female individual in 3-4 at the age of sexual maturity, individual and 5-year-old male around. Young male individual in the position in the lower grades, 7-8 at the age of a chance mating. From the 4-year-old female individual to the 20-year-old, usually once every 2-3 with an annual output of Aberdeen. Although the only giant panda family structure exists only less than 18 months and the mother of the beast between the baby panda will be between sounds and smells through regular exchanges, if not in estrus. One-year-old giant panda baby in about weaning, and has been to 18 months and mother together about his mother again until pregnancy. If not pregnant mother beast, and the baby lives with his mother to two-year-old half, it drove them off when the mother. After independence, most of the baby in the mother's nearby residence, others, especially female, will be living away from the place of birth. Giant pandas need to conduct further research. 。

Captive giant pandas can survive 30 or more, but the life span of wild giant pandas usually only about 20 years. 。

History

Fossils show that giant pandas ancestors appeared in 2-3 million years ago alluvial Ji early. Giant panda habitat in China had covered most of eastern and southern regions, the North of Beijing, the southern and south Vietnam in northern Myanmar (夏勒, 1993). Fossils are usually at an altitude of 500-700 meters in temperate or subtropical forest found. Giant panda habitat only in modern times and the tremendous changes occurred. Over the past few hundred years the Chinese occupation of the land and rapid population growth, many habitat disappeared. Previously, the giant panda had lived in low mountain valley, has now become settlements. Giant pandas only live in the bamboo can grow between elevation 1200-3400 meters. 。

The current distribution 。

The number of wild giant pandas in the end? This is a very difficult question to answer. Living in the high mountain areas on steep slopes of bamboo, the panda statistics become a very hard work. In the 1970s and 1980s have had two surveys, it is estimated that about 1,000 giant pandas field, this figure may be low. Panda regional distribution of the total 37 counties, if by the middle, and a small amount of the general three-tier division, the main producing counties each about 100 around the county, a total of seven counties; general production County each county about 50 more, a total of 11 This projection, the number of wild giant pandas more than 1,000 total only about 1, the number of captive about 100 AAAZPA Communique, 1993). Panda's net reproductive rate of 1.0672, slow population growth (Sichuan precious animal resources Investigation Team, 1977; Bifeng Chau, 1989). Panda Bear Branch family is the most rare, are also under the greatest threat to the survival of the mammals. Giant pandas live in the eastern edge of the Qinghai-Tibet Plateau in southwest China's temperate forests, bamboo is the main understory plants here. Giant panda habitat on six separate mountains: the Qinling Mountains of Shaanxi, Gansu and Sichuan Minshan Mountains, the Qionglai, Sichuan, and the size of the Liangshan Mountain Ridge. The 1980s survey of the habitat area of about 13,000 square kilometers (Reid and Gong 1999). According to the State Forestry Bureau in 2005 investigation report has now confirmed Qinling giant panda population will be identified as a new subspecies of giant pandas. The giant pandas in Qinling pandas in Sichuan and geographical separation of five years has been long on the Qinling pandas head shape than round. At present the number of Qinling pandas have 273. In the Qinling mountains, in black and white pandas found in the brown pandas. 。

Classification dispute 。

The classification status of giant pandas has been more controversial, is to giant panda Xiong ancestors evolved from the class before the panda. Now the internationally recognized it as a Bear Branch, the giant panda subfamily classification, is also gradually domestic recognition. Domestic traditional panda will be a separate classification for the giant panda Branch.。

mating-press吗?

自然交配(Natural mating)。

(一)自然交配(Natural mating)。

指公母畜直接交配。又可根据人为干预的程度分为如下四种方式：

1.自由交配 见于群牧畜群。公母畜常年混牧饲养，一旦母畜发情，公畜即与其随意交配，它是一种不受人工控制的最原始的交配方式。

2.分群交配

在配种季节内，将母畜分成若干小群，每群放入一头或几头经过选择的种公畜，任其自然交配。这样，公畜的配种次数得到适当控制，并实现了一定程度的群体选种选配。但是仍然无法防止生殖器官疾病的传播，公畜的配种利用率仍然有限，母畜的预产期也难于推测。

3.圈栏交配

公母畜平时隔离饲养，当母畜发情时，在圈栏内放入母畜与特定的公畜交配。这种方式在一定程度克服自由交配的缺点，公畜的配种利用率比分群交配有所提高，选种选配也比较严格。

4.人工辅助交配

公母畜平时严格分开饲养，只有在母畜发情配种时，才按原定的选种选配计划，令其与特定的公畜交配，并对母畜作好必要的保定、清毒处理等准备工作，和采取其他一些必要措施，以辅助公畜顺利完成交配。与上述三种自然交配方式相比，增加了种公畜的可配母畜头数，延长了种公畜的利用年限；能够调控产仔时间，有利于生产的计划管理；可以实行严格的个体选种选配，建立系谱，有利于品种改良；根据配种记录，可以估测母畜预产期；并在一定程度上防制疾病传播。它是一种比较科学的人工控制的自然交配方式。

(二)配种时间(mating time)。

结合成受精卵，子宫内着床发育的过程。所以配种必须在最佳时间，使精子和卵子结合，才能达到最佳的受胎效果。在养猪生产中，配种员须掌握每头猪的特性，适时对发情母猪配种。配种最佳时间受以下两方面因素的影响:。

精子在母猪生殖器官内的受精能力:在自然交配后的30分钟内.部分精子可到达输卵管内。交配数小时后，大部分精子存在于子宫体、子宫角内，经15.6小时，大部分精子可在输卵管及子宫角的前端出现。精子在母猪生殖器官内最长存活时间是42小时，实际上精子受精力一般在交配后的25-30小时。

卵子的受精力:卵子保持受精力的时间很短，一般为几小时，最长时间可达15.5小时。

适宜的配种时间:较确切的配种时间是在配种后，精子刚达到输卵管时排卵为最佳时间。但在生产中，这一时间较难掌握。配种时，可按以下规律进行:。

饲养员按压母猪背部，若开始出现静立反射.则在12小时以后及时配种;若母猪发情症状明显，轻轻按压母猪背部即出现静立反射，则已到发情盛期，须立即配种。

配种次数应在两次以上，第一次配种后8-12小时再配种一次，以确保较好的受胎率。据试验报到:母猪在开始接受公猪爬跨后25小时以内配种，受胎率良好，特别是在10-25.5小时可达100%。在以后的时间里配种，成绩较差。

(配种方式给母猪配种一般有三种方式:即“单配，”“复配”和“双重配”。

单配:在母猪发情时.只交配一次。它的优点在于能减轻公猪的负担，可以少养公猪和提高公猪的利用率。但此方法可能降低受胎率和产仔数。

复配:在母猪一个情期内，先后用同一头公猪配两次。即在母猪第一次接受爬跨后先配种一次，在间隔8-12小时后复配一次。其缺点是增加了饲养的公猪数.。

降低公猪利用率，优点可提高母猪的受胎率和产仔数。有资料表明，发情母猪每间隔12小时，连配3次，可提高妊娠率3.4%，平均每窝产活仔数提高0.5头到1.3头。

双重配:在规模化猪场，最好采用双重配的方式，可提高母猪的繁殖成绩。方法是在母猪受精时，用同一品种的两头公猪或它们的精液(人工授精)与其交配。当第一次用一头公猪直配或人工授精，问隔12小时以后，再用另一头公猪直配或人工授精。

优点在于因第一次配种没掌握好适宜的配种时间或第一头公猪的精液品质欠佳引起的损失有所弥补.另可减轻公猪的负担，保证精子的活力，从而可提高母猪的受胎率和产仔。

求英语翻译 机械专业的

翻译为晨曦出版社 。

mating有交配的意思。也有使紧密结合的意思，也可以有配对的意思。press有压的意思，也有坚持强调，衣柜书柜熨斗的意思。

白暨豚的资料(中文和英文）

齿轮是直接接触式（挤压式）的传动装置，是成对运行的，把机械运动和力矩从一个旋转轴传到另一个旋转轴，或从旋转轴传到齿条，是它们保持啮合的突出物叫齿，

齿形；齿轮的接触面必须配合适度，使得传动精准（不丢转）,动力传递不是靠摩擦力，如直接接触式传动装置的描述中所说的，这种传动装置要求无论主动轮还是被动轮，作用力要垂直于接触面，而不是垂直通过轴线，已知的齿轮传动装置的齿形都是渐开线的，它能使得传动不丢转，速比准确，

基本关系；两个啮合的齿轮中小的叫pinion，大的叫gear，当驱动轴是小齿轮pinion时，是减速传动，反之是加速传动，齿轮更多的用于减速传动，如果一个齿轮有n个齿，每分钟n转，n，n的乘积就是每分钟齿（牙）数，如果两个齿轮啮合的好，它们的乘积应该是相等的，即，主动轮齿数X主动轮转速=被动轮齿数X被动轮转速，在齿轮传动中，齿轮的齿数比和速比是由大齿轮的齿数和小齿轮的齿数之比决定的，如果大齿轮齿数100，小齿轮齿数20，速比就是100/20=5，因此小齿轮的转速相当于大齿轮的5倍，因为切点与轴线平高，所以切点叫pitch point（节圆点），它是齿面进行纯滚动接触唯一的点，不平行齿轮和不平行轴 上的齿轮移动式有节圆的，只是节圆的概念有区别，

原文地址：http://www.qianchusai.com/Mating-20.html