White tiger

Historically, the geographical range of tigers extended from Turkey to the Pacific Ocean. However, nowadays tigers have disappeared from most of the areas they once occupied. As a result, they inhabit a wide variety of living environments such as tropical forests, dry forests, oak forests, mangroves, or grass jungles. These felines can cope with significant climate variations as they are found both in hot and humid areas as well as in regions where temperatures can drop to -40°C.

Tigers tend to hunt mostly in the early morning and late afternoon when their favorite prey, the ungulates, are also active. However, the tiger is capable of hunting a wide range of prey. Its diet includes deer, buffalo, domestic animals, as well as bears, young Indian rhinos, tapirs, leopards, crocodiles, turtles, fish, and also porcupines. Studies suggest that they hunt more by hearing and sight than by smell. A stealthy and silent approach at ground level under the cover of vegetation allows the tiger to set up an ambush for its target. It throws its prey off balance by jumping on it and then bites the throat area in order to crush the trachea and suffocate it. If the prey is smaller, it bites directly at the back of the neck to break the spinal cord. The tiger is an effective hunter, but only about 1 in 10 attacks is successful. As a result, when it catches a large prey it is not unusual to see it eat up to 40 kg of meat because it is not certain to eat the next day.

The tiger is a key species for the balance of the ecosystem in which it lives. As a super-predator, it regulates herbivore populations.

The tiger has no predator except the tiger itself, which can attack cubs, and humans.

These solitary felines are active both during the day and at night. Tigers are excellent swimmers and do not hesitate to swim across a river. In fact, they can swim 6 to 8 kilometers without trouble. Despite their size, their powerful legs allow them to be excellent climbers and to make jumps of 8 to 10 meters! They can travel 16 to 32 kilometers per day.

The size of the territory depends on the amount of prey; the higher the density, the smaller the territory. On average, a female’s territory varies between 200 and 1,000 square kilometers, while that of a male can be 2 to 15 times larger! Within this vast area, there are several shelters (cave, hollow tree, etc.). Boundaries are marked using different means. There are olfactory markers such as urine or excrement, which are deposited on trees, rocks, or even on the ground. Also, the tiger marks the environment visually using its claws.

Some individuals fiercely defend their territory, while others coexist without conflict. It can even happen that some individuals move around constantly.

Individuals also communicate with each other using facial expressions and vocalizations. There are many types of vocalizations, such as roaring, growling, meowing, hissing, or whining.

Tigers only meet for reproduction, and it is not uncommon to see confrontations between males for access to a female in heat. The estrus lasts between 3 to 6 days and cycles every 3 to 9 weeks. There is no real breeding season, but there is a peak between November and April. After a gestation period of about 103 days, the female gives birth to between 1 to 7 cubs, with an average of 2 to 3. Tiger cubs are born blind and deaf and weigh only between 780 and 1,600 grams. They will not open their eyes or be able to hear until they are 2 weeks old. From the age of 2 months they begin to follow their mother and start tasting meat. They are completely weaned at around 3 months. The cubs begin to practice stalking, attacking, and killing prey around the age of 5 months. This learning, which can take 3 years, is very important as it determines their ability to survive. Only the mother looks after the young, so she must increase her hunting success rate by 50% to enable her young and herself to survive. The young become independent between 18 months and 3 years, which is why a female only breeds every 3 to 4 years. The survival rate of the young is 50%. Females reach sexual maturity at around 3 to 4 years old, while males do so only around 4 or 5 years old. In the wild, tigers live between 8 and 10 years, but it is not unusual to see individuals as old as 20 years. In captivity, the lifespan is extended and averages 16 – 18 years.

The tiger is in danger of extinction. Estimates, all subspecies combined, indicate that there are only 2,154 to 3,159 individuals remaining. The specific threats to tigers vary by region, but human persecution, poaching for traditional Chinese medicine, habitat destruction for palm oil agriculture, logging, and urbanization threaten tiger populations.

Siberian, South China, and Sumatran tigers are critically endangered. Bengal and Indochinese tigers are threatened. Bali, Javan, and Caspian tigers have already disappeared.

In Asia, forests are cut down to be converted into palm oil plantations. The harvested palm oil is used in many industrial products. These palm oil plantations provide no food for wildlife, which pushes them further away. These uninhabitable areas create natural barriers between different tiger populations. The big cats can no longer reach each other. Populations are isolated and individuals end up breeding with one another, which leads to inbreeding, ultimately causing the decline of the species.

However, in all cases, the white tiger is by no means a full-fledged subspecies of tiger. This particular form of tiger, with blue eyes, completely white fur striped with black bands, is due to a genetic particularity found only in the tiger population in India and perhaps also in Siberia. In fact, they have only been described in the forests of Assam, Orissa, Madhya Pradesh, and Bihar. Hypotheses also mention white tigers in Siberia. Thus, it is not a snow tiger! Moreover, the last reported sighting of a white tiger in the wild dates from 1958 in India. Studies suggest that only one out of 10,000 cubs is born white. This coloration does not allow for camouflage and therefore leads to a quick death of the individual. That’s why white tigers are only seen in zoos and are all descendants of a male named Mohan, captured in 1951.

Contrary to what one might think, they are not albino but leucistic. This genetic trait leads to a lighter coloration of the fur than normal. Indeed, this difference in DNA results in a lower production of melanin, which is the pigment that colors the body’s cells. Having less pigment, the cells are less colored, which results in skin, eyes, and fur lighter than normal. This is called leucism.

This is very different from albinism, which is a genetic difference whose result is a total absence of melanin production. The organism therefore produces no color pigment, which leads to white skin, totally white fur, and transparent eyes that appear red to us due to the blood circulating inside.

White tigers are particular individuals from the Bengal tiger population and possibly Siberian tigers, whose fur color differs from usual. These are individuals with completely white fur, striped with dark brown or black, and with blue eyes.

Contrary to popular belief, they are not albino but leucistic. This is a DNA mutation that leads to a change in an amino acid in a protein. The result is a lower production of one of the melanin pigments, pheomelanin, which is responsible for producing the red, orange, and yellow colors present in tiger fur. Having less red, orange, and yellow pigment means the fur is less colorful, resulting in a white coat. However, there is no effect on eumelanin, responsible for the color of the eyes and stripes.

The individual thus appears white, striped with black, and with blue eyes. This is called leucism. It occurs once in every 10,000 tigers in the wild.

This is very different from albinism, which is a genetic difference resulting in a complete lack of melanin production. The organism produces no pigments at all, which leads to white skin, completely white hair, and transparent eyes that appear red due to the blood circulating inside.

In the wild, they have only been described in the forests of Assam, Orissa, Madhya Pradesh, and Bihar in India. There are also hypotheses of white tigers in Siberia. So, it is not a snow tiger!

The last observation of a white tiger in the wild dates back to 1958. In fact, white tigers are very rare in the wild because their white color provides little camouflage. Therefore, these individuals have a very reduced life expectancy. Furthermore, they are not a distinct subspecies of tiger.

The sum of these elements allows us to affirm that white tigers are not threatened in the wild, simply because they are not present there at all.

At Amnéville Zoo, it is possible to see Orissa, a female white tiger

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