Colouring and coat
The tiger is not to be confused with any other big cat due to its striking stripe pattern. Like the fur coloring with the leopard and jaguar (rosettes) or lion (sand-colored fur), the stripes of the tiger serve the camouflage in combination with the basic color of the fur. Compared to the regular stripes of a zebra, the irregular and partly broken stripes of the tiger are an optimal adaptation to the background of its habitat. The special coloring makes it possible to hide in the vegetation or on the ground. Thus, the black stripes on the golden-yellow or red-orange basic fur color in the bamboo thicket, for example, appear like shadows in the sunlight, and in arid grasslands, the tiger merges with the blades of grass and smaller bushes. In the total perception, the big cat almost "blurs" in its surroundings, and the tiger remains undetected for its prey for a long time. The Siberian tiger is to be made out in the winter only on tree-free, snowy surfaces, whereas the forest gives him again a perfect camouflage, since many trees and bushes in the taiga do not throw off the dry and from the autumn colored leaves.
"The coloration provides the tiger with complete protection. When he moves in the taiga among the bushes and the arid foliage, the black, yellow, and white colors flow entirely into one another, and the animal assumes a monotonous brown-gray color. Especially in autumn, among the orange and red vine leaves and the dry yellow fronds of the bracken, interspersed with many blackish stalks, the tiger can scarcely be distinguished even at a closer distance."
The basic color of the upper side varies depending on the subspecies between golden yellow and red-orange. The underside as well as parts of the face and the insides of the legs are white or light beige. The back of the ears is black and has a clearly conspicuous white marking. Striking dark horizontal stripes extend from the head over the entire rump to the tip of the tail. The tail appears ringed as a result. The legs are striped in similar manner, whereby the front legs show, however, often a clear stripe reduction. The different subspecies of the tiger differ partly considerably in the expression of the fur coloring. The tigers of the Siberian subspecies are usually the lightest colored. However, many Bengal tigers from north or central India are almost of equally light color. The tigers of Indonesia and the Malay Peninsula are usually the darkest and most powerfully colored. Intermediary in the coloring are or were obviously the South Chinese and Caspian tigers. The tigers of the northern populations distinguish themselves beyond that by a larger portion of the white areas. Tigers from the south of the distribution area possess usually many very dark and often also quite wide stripes that often disintegrate at their ends in groups of spots. Such stains occur more rarely with northern tigers. The Caspian tigers from front Asia had relatively narrow, thin stripes on the other hand as a rule. Bengal tigers, which can be quite bright from time to time, differ from old Siberian tigers approximately by the fact that their flank stripes are intensely black, while they are usually gray or brown with the northern form. However, these geographical differences are opposed by a high variability within the populations. The nose of the tiger is generally pinkish-red, but shows with increasing age increasingly black points.
The fur is relatively short with most forms, with the Siberian tigers because of the cold climate, however, densely and long-haired. The length of the hair of a Bengal tiger is in the summer with approximately 8 to 15 mm, with what the hair is longer at the belly with 20 to 30 mm. In contrast, the hair of a Siberian tiger measures 15 to 17 mm on the back and 25 to 45 mm on the belly in summer. The Bengal Tiger's back hair measures 17 to 25 mm long in winter, and the belly hair measures 25 to 40 mm long. The hair of the Siberian tiger reaches a length of 25 to 40 mm on the back and 70 to 105 mm on the belly during the cold season. The body-hairs of the Sumatratiger become only approximately 10 to 15 mm long. However, the long neck-mane and the distinctive whiskers are conspicuous with the males of this subspecies.
At least in zoological gardens, all subspecies develop a winter coat of top coat and undercoat, with hair length and density varying between subspecies and climatic conditions. The summer coat is much shorter and less dense, especially in the Siberian subspecies. The hair density of about 1800 hairs per square centimeter in Bengal tigers and 3200 in Siberian tigers in winter is comparable to that of leopards, although lynxes reach much higher hair densities of up to 9000 per square centimeter. In spring, the long winter coat is replaced by a short summer coat. The impression of a second hair change with northern tigers in the autumn might be explainable by the fact that the summer fur grows out longer in the autumn. Whether tigers in India also carry out a hair change is not quite clear. Also the claws are changed regularly. They first peel off in layers and then fall off. During this time, the tiger often scratches in soft tree bark.
Colour variants
There are, as with most vertebrates, deviant color variants whose peculiarity is less relevant from a biological than from a cultural-historical point of view, since they were bred by local rulers as preciousnesses and are still considered attractions in shows (for example, Siegfried and Roy). White tigers are particularly well known. These animals are not true albinos, but "partial albinos" (leucism), recognizable among other things by the fact that they lack the red eyes of an albino, instead the eyes are usually blue. Most of these white tigers have dark stripes; rarer are white tigers without stripes. Many white tigers known today trace their ancestry to a male captured in the Indian state of Madhya Pradesh in 1951. Since the color variation inherits recessively according to the mendelian rules, inbreeding was a much used means for the breeding of white tigers at the beginning. Contrary to what is often claimed, however, white tigers are not fundamentally a product of inbreeding. Since then, no white tigers have been observed in the wild. Another color variant that is also very rare in the wild is the so-called redling (Rufino), in which the black pigment of the stripes is missing. Such an animal is described approximately from the Elbursgebirge, another from Assam. Such colored animals appeared later also in the offspring of tigers in captivity and are also known under the name "golden tigers". They possess a pale yellow basic color with light brown streak. Tigers of this color variant are bred similar to white tigers particularly in amusement parks and with showmen. The color play types that live today in captivity go back above all to Bengal tigers. Partially, Siberian tigers were in-crossed thereby, why the often propagated "breeding successes" do not represent any contribution to the protection of these subspecies.
Besides white and golden tigers, reports exist about almost black or blue-gray copies. Besides, there are further individual peculiarities in the fur pattern of individual tigers. Thus, some tigers tend to a strong stripe reduction in particular in the area of the front body part.
Height
The size varies greatly between the subspecies. Within a subspecies, the males are recognizably larger and heavier built than the females. Large male tigers of the Siberian or Indian subspecies usually reach a head trunk length of 2 m maximum. In addition, a tail of at least 90 cm. The total length thus lies with approximately 3 m. Females of the Bengal tiger are with tail somewhat over 250 cm long, females of the Amur tiger approximately 260 cm long, with what approximately 165 to 178 cm are allotted to the head trunk length. Sumatran tigers, which represent the smallest living subspecies, reach a total length of 240 to 250 cm (males) or 215 to 230 cm (females). The head-torso-length amounts to 155 to 170 cm (male) respectively 145 to 155 cm (female). The smallest form of the tiger, the extinct Balitiger, might have reached a total length of approximately 220 to 225 cm with male animals and a total length of approximately 190 to 200 cm with female animals.
The withers-height of Siberian tiger-males amounts to in the stand approximately 97 to 105 cm. Males of the Bengal tiger and the Indochinatiger are somewhat smaller with approximately 90 to 100 cm withers. Males of the Sumatratiger measure against it only about 75 to 79 cm, that of the Chinese tiger about 82 to 86 cm. Female Amur, Bengal and Indochina tigers become approximately 78 to 87 cm high. Female Sumatratiger reach a withers-height of only 66 to 68 cm.
Occasionally, also data exist about tigers whose size clearly go beyond the known spectrum. For example, maximum head-torso lengths of 290 cm or total lengths of almost 4 m are reported for tigers. However, such extreme values should be largely based on exaggerations, estimations and/or on measurements with which the length of the animal over curves, thus over all body bends measured, was determined. In addition, skins can be extremely stretched, which can lead to very high values when measured. The longest Caspian tiger that became known is a male that was shot in 1939 at the Ili river and had a length of 295 cm measured in straight distance from the nose tip to the tail tip (between pegs). The head-torso length accounted for 197 cm and the tail for 98 cm. One of the largest credibly surviving total lengths between pegs for a Bengal tiger is 312.5 cm. The average total length of large male Indian tigers is about 280 cm. A huge Siberian male tiger, which came from the Sichote-Alin area and died in the Duisburg Zoo in 1965, measured 319 cm between pegs, of which 99 cm was the tail. The biggest credibly delivered value for the total length of a Siberian tiger amounts to 350 cm over curves, from which a real total length over pegs of approximately 330 to 335 cm results. The animal was killed 1943 in northeast China.
With an average total length of about 260 to 270 cm and rarely over 285 cm, male lions generally lag behind the large subspecies of the tiger. Thus, the tiger can be considered as the biggest cat species of the world. The biggest credibly delivered length measures for lions lie with approximately 305 to 310 cm of total length between pegs, measured at an animal from the area north of the Victoria lake. This is also somewhat below the values for the largest known Siberian tigers.
Body weight
Adult males of the Sumatran tiger weigh about 100 to 140 kg, females between 75 and 110 kg. Male Bengal tigers in Nepal weigh about 200 to 240 kg, females about 125 to 160 kg. The highest, credibly handed down value for the weight of a Bengal tiger is 258 kg according to Vratislav Mazák. The animal was shot in the Terai in India. Another large male of this subspecies weighed 256 kg. The average weight of Indian male tigers is likely to fluctuate around 190 kg, according to Mazák. The highest credible value for a Caspian tiger is 240 kg and was obtained from an animal shot on the Ili River. The highest value for a Siberian tiger is at 306.5 kg, which represents the highest credible documented value of a tiger at all. It was a male named Circa that was captured as a cub in the Ussuri region and died at the age of ten in a menagerie. Data about Siberian tigers with a body weight of clearly over 300 kg are not verifiable. Mazák gives as an average value for the body weight of full-grown Siberian tigers about 230 kg. The extinct Balitiger reached presumably only a body weight of 90 to 100 kg (male) respectively 65 to 80 kg (female). Java tigers were somewhat larger with a body weight of approximately 130 to 135 kg (male) and approximately 100 kg (female).
Skull and dentition
Like other big cats, the tiger also has a round pupil. The iris is usually yellow. The massive skull of the tiger is more elongated than that of small cats, as with other big cats. It is similarly large as that of the lion and hardly to be distinguished from a lion skull. In the construction of the nose bone, smaller differences exist, as well as in the construction of the lower jaw. This is rather concave with the tiger at the underside while that of the lion is rather convex bent. The skull length amounts to 350 to 360 mm on average with big tiger males. The skull lengths of bigger female tigers lie with approximately 290 to 310 mm, whereby sumatratiger only skull lengths of 295 to 340 mm (male) respectively 263 to 293 mm (female) show. The skull length of full-grown, male Balitiger amounted to only approx. 295 mm, that of the females approx. 265. The brain of the tiger holds approx. 250 to 300 cm³.
The permanent dentition contains 30 teeth, with the dental formula corresponding to that of other recent cats:
The first upper molar (cheek tooth) is very small or often missing completely. The same applies to the first upper premolar. Most conspicuous are the canines (canini), which in the upper jaw protrude up to 70 mm from the gum. The lower canines are slightly shorter. The fangs are placed by the fourth upper premolar and the first lower molar and are 34 to 38 mm and 26 to 29 mm long respectively in adult tigers.
Skeleton and internal organs
The skeleton is a typical cat skeleton and hardly distinguishable from that of a lion. Only at the humerus (upper arm bone), slight differences are to be made out. The tiger possesses a retractable, sickle-shaped claw at each toe of the front paw. These can reach 80 to 100 mm at the outside and are hidden in the resting state in skin sheaths. At the rear foot, the visible four toes are also provided with retractable claws. The spinal column of the tiger consists of 55 to 56 vertebrae, the rib cage of 13 rib pairs. A tiger heart weighs about 600 to 1100 g, the intestine measures about 7 m. Amur tigers usually put on a thick layer of fat in winter, the thickness of which is about 5 cm on the flanks.
Chromosome set
The chromosome set of the tiger consists as with other old-worldly cats of 18 autosome pairs and two sex chromosomes, what results in a diploid set of 38 chromosomes.
Track
The step length of the tiger varies between 70 cm with males and 60 cm with females. The size of the paw prints depends strongly on the underground. The front paws of a very big male tiger leave an imprint of about 14 to 17 cm length and 13 to 16 cm width in moist clay. The tread marks of female tigers measure 12 to 14 cm in length, 11 to 13 cm in width under these conditions. In the snow, in particular in the new snow, the tracks can turn out clearly bigger.
