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Freak Specimens
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 (03-08-2019, 11:21 AM)Spalea Wrote: when I see the black tiger's ones. Now I know they really existNo that's not black tiger, it's fake pic of Black and White tiger together. Although melanistic tigers are rare. Most of them are Partial Black which now living and observed in Similipal (odisha) and others. But, there are reports from various places in the past about their existence. Black tigers, which get their evenly coat from melanism just like black panthers, are a very rare sight indeed, either in the wild or in captivity. There have reports during the British colonization of India in the 18th century and in the 1910s, but these reports are now lost. *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author The melanistic cats are color variants of the orange Bengal tiger (not from other tigers like Amur etc.., as far as I Know), which survives naturally in the wilderness of India, Nepal, Bangladesh and Bhutan. But sights are rare in the wild, especially since tigers are elusive; instead, they’re more often found in captivity – for example, in July 2014, in the Indian zoo of Nandankanan Zoological Park (northeast of India- Odisha), a white tigress gave birth to four cubs, one of which was black; it was the first instance of a black tiger’s birth in captivity, and the second recorded instance internationally. White Tigers that Turn Black Pseudo-melanistic, or “black” tigers: – where did they come from, and why are they suddenly popping up now in the captive white tiger population ? “Black” Cubs Born in Captivity  *This image is copyright of its original author Sembian with his mother Anu, at Arignar Anna Zoo, Vandalur. Photo by Fightingfalcon2005 (CC BY-SA 3.0 ) In June 2010, a white tiger pair (Anu and Bhishmar) at the Arignar Anna Zoo in Vandalur, India, had their 2nd litter of 3 white tiger cubs. One of these cubs was different – his white coat appeared to be turning black! As the cub, Sembian, matured, it became apparent that the blackness was due to an expansion of the normal black stripes, termed “abundism” or more popularly called “pseudo-melanism”. Sembian’s coat had a white background with an over-abundance of blackness – his black stripes were so wide they ran together in places. [Source] – Plus many other news report  *This image is copyright of its original author Pseudo-melanistic tigers at Nandankanan zoo. Photo by PALLABI SEN (Own work) (CC BY-SA 4.0) In July 2014, it happened again, this time at the Nandankanan Zoo in Orissa, India, and this time the litter of 4 was a mixture of white and orange cubs born to Sneha and Manish, a white mother and orange father. Two cubs, 1 white and 1 orange, had the overabundance of black stripes . In May 2016 another pair at the zoo – Renuka and Samrat – had one pseudo-melanistic cub (stillborn). In August 2016 the first pair had another litter of 3 cubs – again, one cub was pseudo-melanistic. [Source1] [Source2] [Source3] plus many other news reports At first, the “black” cubs were thought to be “accidents” of nature, or “mutants” – but after the 2016 litters the zoo realised they were dealing with normal genetic inheritance. The Theory  *This image is copyright of its original author Pseudo-Melanistic white tiger at Nandkanan Zoo. Pseudo-melanism in tigers appears to be caused by a recessive gene – similar to the white gene, but separate from it as it can affect both white and orange tigers. This would mean that a “normal” orange or white tiger can carry the melanistic gene in a hidden state, as it is masked by the dominant allele. So assuming it is an inherited trait, a trace of the pseudo-melanistic tigers’ pedigree should give us a clue where it came from. This leads back to 5 wild-born ancestors that all the melanistic cubs have in common: Mohan and Begum of the Rewa line, and Pradeep, Sikha and Rani of the Orissa line. [Source; and Bengal Tiger Studbook Dec 2012] It is highly unlikely that the gene came from the Rewa tigers, as it should have shown up earlier during the inbreeding that occurred in the first few generations of that line. That leaves the 3 from the Orissa line, and a glance at the origin of these 3 tigers shows an obvious candidate : Rani. Rani, an orange tigress, and one of the founders of the Orissa line of white tigers, was found wild in the Similipal forests in 1967, as a little 7wk old cub. [Source: Birth of White Tiger Cubs to Normal Coloured Tigers in Captivity, by CH G Mishra, L N Acharjyo, L N Choudhury in JBNHS vol 79 1982.]  *This image is copyright of its original author Location of Similipal Forests. Source: Google Maps The Similipal Tiger Reserve had for many years been rumoured to harbour “black” tigers, – rumours that were widely dismissed as myth until 1993 when proof was obtained (the skin of a slain tiger). [Sources: Born Black – The melanistic Tiger in India by L A K Singh. WWF India. Sept 1999; “Black Tigers” – Reality or Myth by Dr L A K Singh, in WWF Tiger Update, v1 No 4, Oct 1996; Black on white or White on Black… by BC Prusty and LAK Singh, in Zoos’ Pring, v XII, No 1, Jan 1997; Black Tigers of Similipal Tiger Reserve, Orissa by G H Mishra, in Indian Forester, V122, No 10, Oct 1996.] Since then these pseudo-melanistic orange tigers have been photographed by camera traps in the reserve, and it was estimated that there were 3 of them living there in 2014. The Similipal tiger population is threatened, with only an estimated 26 tigers left there in 2016. [Source1; Source2; Source3] Back in 1975, in the Nandankanan zoo, Rani the Similipal tigress mated with Deepak, an orange male who was later found to carry the white gene. Apparently Rani passed the melanistic trait on to her daughter Ganga (also a white gene carrier), who then passed it on to one or more of her many cubs. Throughout the next 3 or 4 generations, the recessive melanistic gene gradually spread unnoticed throughout the Nandankanan tiger population, until finally 2 melanistic gene carriers were paired together.  *This image is copyright of its original author Possible path of pseudo-melanism inherited from tigress Rani. Note: Abbreviated chart. Meanwhile, in 1999, Laxman, a white male tiger from the Orissa line, was sent to the National Zoological Park in Delhi to breed with their Rewa line white tigers. Laxman was also descended from Rani, and it is possible that he carried the melanistic gene and passed it to some of his descendants, including Anu and Bhishmar, who became the parents of the blackened Sembian. [note i] There have been too few melanistic births to be certain which of Ganga’s offspring carried the trait, as it is not likely she passed it to all her cubs. A study of the full birth charts shows the most likely option to be Debabrata plus either Pinaki or Jamuna. This abbreviated chart above shows the possible line of inheritance. Please note that this chart does not show all the generations and tigers involved. For full (and complicated!) details please refer to the ancestry charts in White Tigers Today.. Is it Caused by Inbreeding? Inbreeding is one way that a recessive trait can show up. However, the expression of a recessive trait does not automatically signify inbreeding, but simply that a trait has had time to be distributed throughout a population unnoticed (because it is masked by the dominant allele). This late showing of a recessive trait that has been present in the captive population since 1967, illustrates how careful the zoos have been to avoid close inbreeding in the Orissa line of white tigers. [note ii] It has taken all this time for the gene(s) to spread throughout the population – the Nandankanan pseudo-melanistic cubs are 4 generations removed from any common ancestor, and SIX generations removed from the presumed origin, the tigress Rani. Significance for White Tigers and Tigers in General Occurrence of White Tigers in the Wild This concept of a recessive trait spreading unnoticed throughout a population (see above) is also important in understanding the occurrence of white tigers in the wild. They did not just pop up here and there spontaneously – 1 in 10,000 – as often suggested, but the hidden white gene seems to have spread from NE India through to Central India, in time becoming so common in some areas that white tigers were born more frequently in these areas – eg Rewa and Bihar. [Source1; Source2; Source3] Captive Populations Preserving Genetic Diversity As Rani’s daughter Ganga also carried the white gene (from her father Deepak), she was bred extensively and has many descendants in the captive population today. In the effort to preserve the white gene, the zoos have inadvertantly also preserved other tiger genetic diversity that is endangered in the wild. The pseudo-melanistic trait is a visible example of this, but there is likely much more variation thus preserved that we cannot see with the eye. “Real” Tigers Come in Many Colours Throughout history, hunters and naturalists have observed and recorded wild tigers in a startling array of coat colour variations –
Conclusion  *This image is copyright of its original author “Black” tiger in Nandankanan Zoo. Photo by Jitendraamishra (Own work) (CC BY-SA 4.0) The pseudo-melanistic trait arose naturally in the wild, where it apparently survives only in Similipal today. Fortuitously, one tigress from this area was taken into captivity 50 years ago and bred, thus preserving some of the unique genetic diversity of the tigers from that area. It is highly likely that Rani, the little wild cub from Similipal, carried the pseudo-melanistic trait and passed it on to her daughter Ganga, who passed it on to one or more of her own cubs. As the Simlipal population is currently threatened, this is another instance of captive tigers (both white and orange) serving as a reservoir of genetic diversity that is endangered in the wild. Notes Amongst Anu and Bhishmar’s 13 cubs there were no other reported melanistic cubs. This might indicate that there are other factors influencing or suppressing the trait. [ii] There was only one father-daughter pairing, that of Deepak to Ganga. Offspring were then outcrossed to the unrelated Rewa line, and I have not found any further parent-child or sibling pairings at Nandankanan. In recent years they have also outcrossed to wild tigers, thus strengthening their gene pool further. The initial breeding of Ganga to her father Deepak would not have produced pseudo-melanistic cubs as we assume that only Rani (not Deepak) carried the gene, which she then passed to her daughter Ganga. @Spalea Hope this helps... 
@Sanju :
Thank you very much for your long answer at #727. I shortly and diagonally read the facebook page concerning the black tiger (in english, the french version doesn't exist). And yes I was a bit abused by one of your photo at the #720. In fact, so, we speak about cases of pseudo melanism or "abundism"... Specific to this place, the Similipal forest. From @turpentinecreek White tigers are not "albino" tigers nor or they a separate subspecies. Their coloring is a genetic mutation that would be considered a hindrance in the wild because it does not provide adequate camouflage for survival. This means white tiger breeding is not done for conservation, but rather, for profit because they are "pretty." Cub-petting and entertainment industries, along with private owners value these animals for their looks. Due to the inbreeding required to obtain this color variant, about 80% die from debilitating health defects and only 1/30 are "pretty" enough to be "valuable" dollar-wise. While white tigers at a facility can sometimes be a red flag, TCWR is home to 17 plus two golden tabby tigers. As a true sanctuary, we do not breed, buy, sell, or trade animals. We exist not for profit or entertainment, but essentially as a "big cat" animal shelter for displaced survivors of the Exotic Pet Trade. By supporting TCWR, you are not supporting unethical white tiger breeding; you are supporting a better life for these animals and helping us put an end to the Trade.   (03-16-2019, 06:11 PM)Apollo Wrote: You dont fcuk with this tiger Damn this was funny, I laughed with watery eyes  It reminded me of my former dog, when it saw a cat. But forgot, that it was attached to the leash and run until.... well, luckily dogs have strong neck. At that time I was a bit scared, that did it kill itself, when it made a forward flip, when leash tightened. But after I saw, that only pride was hurt...  But yes, quite eager tiger, no question about it!  |
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