Recently, an amateur photographer in India took a group of photos in Nandankanan National Park, which aroused the interest of many netizens.
Speaking of tigers, it usually looks like this.
But the two male tigers in this set of photos have a slightly unique pattern.
The black stripes on their bodies are much denser than those of ordinary tigers, and the stripes are close together, covering the orange fur in the middle.
The color of the black stripes is also relatively dark, and from a distance, the body looks black and connected.
For example, on the tail, the tiger's tail generally has a circle of stripes,
The tails of these two tigers are almost all black,
There is also a large area of black on the back.
Therefore, many reports call them "black tigers".
Two black tigers can be photographed, in fact, it is purely accidental,
Experts say that in the past few years there have been only seven or eight black tigers left in the Similal region of Odisha,
It is already quite difficult to see the real face, and it is even luckier to see 2 of them at once.
The lucky one recently took this photo shoot, Satya Swagat, a 23-year-old college student studying business in New Delhi.
He loves photography and works as an amateur photographer in his spare time, inadvertently capturing the figure of a black tiger.
The photo was taken last November, when Satya suddenly saw two black tigers 30 feet away.
Speaking of that experience, he was still very excited.
"The first time I saw a black tiger, I got goosebumps."
"I couldn't believe my eyes, I forgot to pick up the camera for a minute because these big cats were dangling right in front of my eyes."
Satya said he had heard about the Black Tiger from friends who had been to Nandankanan National Park before.
But few people have actually seen them in the forest, and not many people can photograph black tigers so close.
"I had the opportunity to photograph a tiger in 2020, but at the time, circumstances were limited and I didn't get any decent photos."
"But this time it's different, everything is just right, and it's not just one, it's two."
Centuries ago, there were many wild tigers in India, but there were not many such black tigers.
As early as 1772, the artist James Forbes reportedly painted a black tiger, proving that someone had already seen the black tiger at that time;
In the late 18th century, it was recorded that indian natives and British hunters saw or captured black tigers in central and northeastern India;
(Schematic, captured black tiger)
In Burma in 1913, and in China in the 1950s, there were rumors of the appearance of a black tiger;
(Black Tiger in Oriental Painting)
Black tigers have been seen in the Similal region of the Indian state of Odisha since 1993, and have only appeared there since 2007;
In August 2020, an amateur photographer happened to take a picture of a black tiger there, which also caused a sensation at the time.
In the past, when people saw the black tiger, they would say that it ran out of mythology.
In recent years, people have become more and more curious about why they look like this.
After the research of scientists, there are finally preliminary results.
Simply put, the unique pattern of the black tiger is the result of a genetic mutation.
The cause of genetic mutations is because of inbreeding.
Uma Ramakrishnan, an ecologist at the National Centre for Biological Sciences (NCBS) in Bangalore, and her student Vinay Sagar, lead a team to conduct the research,
Last September, the study was published in the Proceedings of the National Academy of Sciences.
(Press reports at the time)
The study found that the black tiger's body appeared so many black stripes because of a mutation in a gene called Taqpep (full name Transmembrane Aminopeptidase Q).
Just at position 1360 of the Taqpep gene sequence, the change from cytosine to thymine triggered a huge change in the appearance of the black tiger.
After the occurrence of genetic mutations, it will lead to pseudomelanisticism, which makes the melanin deposit abnormally serious.
That is to say, the black tiger is a Bengal tiger with pseudo-blackening.
This gene that triggers pseudo-melanosis is a recessive gene.
The little tiger inherits half of the genes from the father and the mother, respectively, and this recessive gene is only manifested when the dominant gene is missing.
If both parents carry this recessive gene, then the baby tiger cubs they give birth to are one in four chances of being black tigers.
However, the odds that two tigers, one male and one female, carry the same gene and pass it on to the next generation are very small
The researchers performed whole genome sequencing analysis on tigers with pseudo-melanosis and tigers with common stripes.
Eventually, the genetic mutation that triggers pseudomelanosis was found.
Moreover, the researchers combined genetic information analysis and computer simulation data from other tiger populations in India to analyze their genes.
Discover the black tigers of this place in The Silhouette, whose ancestral range may have been very small,
The original ancestors may have only a few tigers.
Tigers in India come mainly from three genetic populations, namely southern, northwestern and central India.
The report points out that tigers in the Similipal region are an isolated population in eastern India, unlike the three above.
Due to geographical barriers, their genetic communication with other tiger populations is very limited.
Tigers isolated in the Similal region have mated with inbreeds for several generations, that is, inbreeding.
Inbreeding leads to genetic mutations, which in turn trigger pseudomelanosis.
In tigers in the Similipal region, the probability of genetic mutation is very high, up to 58%,
That's why black tigers appear in the local area.
According to the results of the 2018 Tiger Population Census, there are about 2967 tigers in India.
In the same year, a total of 8 tigers were photographed in the Similipal area,
Three of them are "pseudo-melanization tigers", characterized by wide black stripes that combine them.
In addition to the wild black tiger in the Similipal region, there are a few other black tigers, which now live in three zoos in India, and are also born in zoos.
Genetic tracking found that these captive tigers shared a common ancestor with tigers in the Similal region.
(Black Tiger in the Zoo)
Almost all of the black tigers found in India now come from tiger populations in the Similipal region.
The researchers were curious as to why the probability of a genetic mutation in a black tiger occurring in this place was so high.
There is currently such a hypothesis -
Most other tigers in India live in plains, open, dry, well-lit,
The Similal region is tropical and subtropical jungle with lush vegetation and darker light.
The darker body color of the black tiger is more suitable for ambushing when hunting in the Similal area, and it is also easier to hide and avoid the pursuit of hunters.
So if you live in the Minilipal area, these black tigers have certain advantages.
Figuring out the above is of great significance to the issue of tiger protection,
Because scientists now understand that this relatively isolated, close-to-inbreed tiger population is particularly prone to extinction in a short period of time and must be protected as soon as possible.
The reason why the tiger population in the Similipal area is isolated is that humans cannot be separated.
Centuries of human activity have divided tigers' natural habitats into chunks, which has led to the isolation of tiger populations in different regions, which in turn leads to inbreeding.
Ecologist Ramakrishnan said tiger populations in parts of India have recovered, but there are still several small and isolated populations.
They all face genetic drift (i.e., random fluctuations in gene frequency due to changes in the number of offspring of individuals of different genotypes in small groups), inbreeding, and degradation or decline in survival caused by inbreeding.
To sum up, these populations are more likely to go extinct.
Over time, the introduction of fresh genes into isolated populations can reverse these harms.
Tigers from other populations can be artificially airlifted over and integrated into isolated populations, but this is not a long-term solution.
In the long run, there is only one way to protect them from extinction.
That is, to maintain or restore tiger habitats so that there is natural connectivity between habitats.
Only then will tigers from different populations have the opportunity to come into contact with each other and produce healthier offspring...