Tuesday, March 6, 2012

Harimau-Harimau nan Memukau

Postingan kali ini menampilkan Harimau-harimau yang cantik dan memukau. Beberapa dari mereka adalah hasil dari persilangan, dan sangat jarang dijumpai di alam liar


White Tiger

The white tiger is a recessive mutant of the Bengal tiger, which was reported in the wild from time to time in Assam, Bengal, Bihar and especially from the former State of Rewa.

Compared to normal colored tigers without the white gene, white tigers tend to be larger, both at birth and as fully grown adults. Kailash Sankhala, the director of the New Delhi Zoo in the 1960s, said "one of the functions of the white gene may have been to keep a size gene in the population, in case it's ever needed." Dark-striped white individuals are well-documented in the Bengal Tiger subspecies, also known as the Royal Bengal or Indian tiger (Panthera tigris tigris or P. t. bengalensis), and may also have occurred in captive Siberian Tigers (Panthera tigris altaica), as well as having been reported historically in several other subspecies.

Currently, several hundred white tigers are in captivity worldwide, with about one hundred being found in India. Nevertheless, their population is on the increase. The modern white tiger population includes both pure Bengals and hybrid Bengal–Siberians, however, it is unclear whether the recessive white gene came only from Bengals, or if it also originated from Siberian ancestors.


The unusual coloration of white tigers has made them popular in zoos and entertainment showcasing exotic animals. German-American magicians Siegfried & Roy became famous for breeding and training two white tigers for their performances, referring to them as "royal white tigers", the white tiger's association with the Maharaja of Rewa.

Rewa Maharaja Martand Singh first observed male white tiger Mohan during his visit to Govindgarh jungle at Rewa, Madhya Pradesh, India. After hunting for months, he was able to capture the first living white tiger seen in nature. With help from official veterinary experts, he unsuccessfully tried to breed the white tiger with colored female tigers. Eventually, however, he succeeded in creating a second generation of white tigers. In time, it expanded around the world.




Snow White Tiger

An additional genetic condition can remove most of the striping of a white tiger, making the animal almost pure white. One such specimen was exhibited at Exeter Change in England in 1820, and described by Georges Cuvier as "A white variety of Tiger is sometimes seen, with the stripes very opaque, and not to be observed except in certain angles of light." Naturalist Richard Lydekker said that, "a white tiger, in which the fur was of a creamy tint, with the usual stripes faintly visible in certain parts, was exhibited at the old menagerie at Exeter Change about the year 1820." Hamilton Smith said, "A wholly white tiger, with the stripe-pattern visible only under reflected light, like the pattern of a white tabby cat, was exhibited in the Exeter Change Menagerie in 1820.", and John George Wood stated that, "a creamy white, with the ordinary tigerine stripes so faintly marked that they were only visible in certain lights." Edwin Henry Landseer also drew this tigress in 1824.

The modern strain of snow white tigers came from repeated brother–sister matings of Bhim and Sumita at Cincinnati Zoo. The gene involved may have come from a Siberian tiger, via their part-Siberian ancestor Tony. Continued inbreeding appears to have caused a recessive gene for stripelessness to show up. About one fourth of Bhim and Sumita's offspring were stripeless. Their striped white offspring, which have been sold to zoos around the world, may also carry the stripeless gene. Because Tony's genome is present in many white tiger pedigrees, the gene may also be present in other captive white tigers. As a result, stripeless white tigers have appeared in zoos as far afield as the Czech Republic, Spain and Mexico. Stage magicians Siegfried & Roy were the first to attempt to selectively breed tigers for stripelessness; they owned snow-white Bengal tigers taken from Cincinnati Zoo (Tsumura, Mantra, Mirage and Akbar-Kabul) and Guadalajara, Mexico (Vishnu and Jahan), as well as a stripeless Siberian tiger called Apollo.


In 2004, a blue-eyed, stripeless white tiger was born in a wildlife refuge in Alicante, Spain. Its parents are normal orange Bengals. The cub was named Artico ("Arctic").

Stripeless white tigers were thought to be sterile until Siegfried & Roy's stripeless white tigress Sitarra, a daughter of Bhim and Sumita, gave birth. Another variation which came out of the white strains were unusually light-orange tigers called "golden tabby tigers". These are probably orange tigers which carry the stripeless white gene as a recessive. Some white tigers in India are very dark, between white and orange.




Golden Tiger
A golden tabby tiger is one with an extremely rare color variation caused by a recessive gene and is currently only found in captive tigers. Like the white tiger, it is a color form and not a separate species. In the case of the golden tiger, this is the wide band gene; while the white tiger is due to the color inhibitor (chinchilla) gene. There are currently believed to be fewer than 30 of these rare tigers in the world, but many more carriers of the gene.

While no official name has been designated for the color, it is sometimes referred to as the strawberry tiger due to the strawberry blonde coloration. The golden tiger's white coat and gold patches make it stand out from the norm. Their striping is much paler than usual and may fade into spots or large prominent patches. Golden tigers also tend to be larger and, due to the effect of the gene on the hair shaft, have softer fur than their orange relatives.

Like their white cousins, all golden tabby tigers have mainly Bengal parentage, but are genetically polluted with the genes of the Amur tiger via a part-Amur white tiger called Tony, who is a common ancestor of almost all white tigers in North America. The suggestion that this coloration is caused through the deliberate breeding of Amur tigers with Bengal tigers is a popular myth founded on this fact. All golden tigers appear traceable to one of Tony's male descendants, Bhim.


India has records of wild golden tigers which date back as far as the early 1900s. There have been suggestions that the tendency for this coloration gradually developed in a small group of tigers living in an area of heavy clay concentration. The unusual color would provide these tigers with extra camouflage. The theory remains unproven, however, inbreeding of a small isolated group of tigers could cause the recessive golden tiger gene to emerge if at least one of those tigers carried the recessive gene for the golden color and bred with its own offspring Golden tigers may occur in the same litter as stripeless or nearly stripeless tigers. This is due to the effect of the wide-band gene on the normal orange color and the white color respectively. The wide band mutation is not found solely in white tigers and may also be carried by normal coloured tigers, however carriers of the wide band gene are probably no longer found in the wild. Wild-born golden tigers might be disadvantaged as they are less well camouflaged than normal orange tigers. The last known wild Golden tigers were shot outside of Mysore Pradesh, India in the early 20th century.




Maltese Tiger

The Maltese tiger, or blue tiger, is a semi-hypothetical coloration morph of a tiger, reported mostly in the Fujian Province of China. It is said to have bluish fur with dark grey stripes. Most of the Maltese tigers reported have been of the South Chinese subspecies. The South Chinese tiger today is critically endangered, and the "blue" alleles may be wholly extinct. Blue tigers have also been reported in Korea, home of Siberian tigers.

The term "Maltese" comes from domestic cat terminology for blue fur, and refers to the slate grey coloration. Many cats with such colouration are present in Malta, which may have given rise to the use of the adjective in this context.

Around 1910, Harry Caldwell, an American missionary and big game hunter, spotted and hunted a blue tiger outside Fuzhou. His search is chronicled in his book Blue Tiger (1924), and by his hunting companion Roy Chapman Andrews in his Camps & Trails in China (1925, chapter VII). Chapman cites Caldwell thus:

The markings of the beast are strikingly beautiful. The ground colour is of a delicate shade of maltese, changing into light gray-blue on the underparts. The stripes are well defined and like those of the ordinary yellow tiger.
Caldwell, Chapman (1925)


A more recent report, given to Mystery Cats of the World author Karl Shuker, comes from the son of a US Army soldier who served in Korea during the Korean War. His father sighted a blue tiger in the mountains near what is now the Demilitarized Zone. Blue tigers have also been reported from Burma. The black tiger was also long considered mythical, but several pelts have proven that pseudo-melanistic or hypermelanic tigers do exist. They are not wholly black, but have dense, wide stripes that partially obscure the orange background colour.




Liger

The liger is a hybrid cross between a male lion (Panthera leo) and a tigress (Panthera tigris). Thus, it has parents with the same genus but of different species. It is distinct from the similar hybrid tiglon. It is the largest of all known extant felines. Ligers enjoy swimming, which is a characteristic of tigers, and are very sociable like lions. Ligers exist only in captivity because the habitats of the parental species do not overlap in the wild. Historically, when the Asiatic Lion was prolific, the territories of lions and tigers did overlap and there are legends of ligers existing in the wild. Notably, ligers typically grow larger than either parent species, unlike tiglons which tend to be about as large as a female tiger.

The liger is the largest known cat in the world. Imprinted genes may be a factor contributing to huge liger size. These are genes that may or may not be expressed on the parent they are inherited from, and that occasionally play a role in issues of hybrid growth. For example, in some dog breed crosses, genes that are expressed only when maternally-inherited cause the young to grow larger than is typical for either parent breed. This growth is not seen in the paternal breeds, as such genes are normally "counteracted" by genes inherited from the female of the appropriate breed.

Other big cat hybrids can reach similar sizes; the litigon, a rare hybrid of a male lion and a female tiglon, is roughly the same size as the liger, with a male named Cubanacan (at the Alipore Zoo in India) reaching 363 kg (800 lb). The extreme rarity of these second-generation hybrids may make it difficult to ascertain whether they are larger or smaller, on average, than the liger.


It is erroneously believed that ligers continue to grow throughout their lives due to hormonal issues. It may be that they simply grow far more during their growing years and take longer to reach their full adult size. Further growth in shoulder height and body length is not seen in ligers over 6 years old, same as both lions and tigers. Male ligers also have the same levels of testosterone on average as an adult male lion, yet are azoospermic in accordance with Haldane's rule. In addition, female ligers may also attain great size, weighing approximately 320 kg (705 lb) and reaching 3.05 m (10 ft) long on average, and are often fertile. In contrast, pumapards (hybrids between pumas and leopards) tend to exhibit dwarfism.




Tiger's Family Photo


Subhanallah




Source: Wikipedia

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