| Caspian tiger | |
|---|---|
| Captive Caspian tiger, Berlin Zoo, 1899 | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Felidae |
| Subfamily: | Pantherinae |
| Genus: | Panthera |
| Species: | Panthera tigris |
| Subspecies: | P. tigris virgata |
| Trinomial name | |
| Panthera tigris virgata Illiger, 1815 |
|
| Original distribution (in red) | |
The Caspian tiger, also known as the Turan tiger and Hyrcanian tiger, is an extinct tiger subspecies that has been recorded in the wild until the early 1970s, and used to inhabit the sparse forest habitats and riverine corridors west and south of the Caspian Sea, from Turkey, Iran and west through Central Asia into the Takla Makan desert of Xinjiang, China. There are no individuals in captivity.[1]
The Caspian tiger was formerly found in Chinese and Russian Turkestan, Afghanistan, Iran, and Turkey.[2]
The Caspian tiger together with the Siberian and Bengal tiger subspecies represented the largest living felid and ranked among the biggest felids that ever existed.[3]
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The body of Caspian tigers was generally less massive than of Siberian tigers, and their average size slightly less. In Turkestan, male tigers exceeded 200 cm (79 in) in length, though an estimated body length of 270 cm (110 in) was recorded. Females were smaller in size, normally ranging between 160 to 180 cm (63 to 71 in). The maximum known weight was 240 kg (530 lb). Maximum skull length in males was 297.0 to 365.8 mm (11.69 to 14.40 in), while that of females was 195.7 to 255.5 mm (7.70 to 10.06 in). Although tigers from Turkestan never reached the size of Siberian tigers, there are records of very large individuals. In January 1954, a tiger killed near the Sumbar River in Kopet-Dag had a skull length of 385 mm (15.2 in), which is considerably more than the known maximum for this population and slightly exceeds that of most Siberian tigers.[4]
The main background colour of its pelage varied, though generally, it was brighter and more uniform than that of Far Eastern tigers. The stripes were narrower, fuller and more closely set than those of the Siberian tiger. The colour of its stripes were a mixture of brown or cinnamon shades. Pure black patterns were invariably found only on the head, neck, the middle of the back and at the tip of the tail. Angular patterns at the base of the tail were less developed than those of the Far Eastern populations. The contrast between the summer and winter coats was sharp, though not to the same extent as in Far Eastern populations. The winter coat was paler, with less distinct patterns. The summer coat had a similar density and hair length to that of the Bengal tiger, though its stripes were usually narrower, longer and closer set.[4]
At the turn of the century, researchers from the University of Oxford, the U.S. National Cancer Institute and the Hebrew University of Jerusalem collected tissue samples from 23 Caspian tiger specimens kept in museums across Eurasia. They sequenced at least one segment of five mitochondrial genes, and observed a low amount of variability of the mitochondrial DNA in P. t. virgata as compared to other tiger subspecies. They re-assessed the phylogenetic relationships of tiger subspecies and observed a remarkable similarity between Caspian and Amur tiger indicating that the Amur tiger population is the genetically closest living relative of the extinct Caspian tiger, and strongly implying a very recent common ancestry for the two groups. Phylogeographic analysis suggested that less than 10,000 years ago the ancestor of Caspian and Amur tigers colonized Central Asia via the Silk Road from eastern China, then traversed Siberia eastward to establish the Amur tiger in the Russian Far East. The actions of industrial-age humans may have been the critical factor in the reciprocal isolation of Caspian and Amur tigers from what was likely a single contiguous population.[5]
Historical records show that the distribution of Caspian tigers in the region of the Caspian Sea was not continuous but patchy, and associated with watercourses, river basins, and lake edges. In the 19th century, they occurred
Their former distribution can be approximated by examining the distribution of ungulates in the region.[6] Wild pigs were the numerically dominant ungulates occurring in forested habitats, along watercourses, in reed beds and in thickets of the Caspian and Aral seas. Where watercourses penetrated deep into desert areas, suitable wild pig and tiger habitat was often linear, only a few kilometers wide at most. Red and roe deer occurred in forests around the Black Sea to the western side and around the southern end of the Caspian in a narrow belt of forest cover. Roe deer occurred in forested areas south of Lake Balkash. Bactrian deer occurred in the narrow belt of forest habitat on the southern border of the Aral Sea, and southward along the Syr-Darya and Amu-Darya rivers.[4]
There is no data available for home ranges of Caspian tigers.[7] In search of prey, Caspian tigers were compelled to prowl widely and follow ungulates from one pasture to another. Wild pigs and cervids formed their main prey base. In many regions of Middle Asia, Bactrian deer and roe deer were important prey species apart from wild pigs. Occasionally, they also preyed on Caucasian red deer, on goitered gazelle in Iran, on jackals, jungle cats, locusts and other small mammals in the lower Amu-Darya River area, on saiga, wild horses, Mongolian Wild Ass and mountain sheep in the Zhana-Darya and around the Aral Sea, and on Manchurian wapiti and moose in the Baikal area. They followed herds of migratory prey species like reindeer, and caught fish in flooded areas and irrigation channels. In winter, they frequently attacked dogs and livestock straying away from herds. They preferred drinking water from rivers, and drank from lakes in seasons when water was less brackish.[4]
The demise of the Caspian tiger began with Russian colonization of Turkestan during the late 19th century.[8] Their extirpation was a process intensified by several circumstances:
Until the early 20th century, the regular Russian army was used to clear predators from forests, around settlements and potential agricultural lands. Until World War I, about 50 tigers were killed alone in the forests of Amu-Darya and Piandj Rivers each year. High incentives were paid for tiger skins up to 1929. Wild pigs and deer, the prey base of the tigers, was decimated by deforestation and subsistence hunting by the increasing human population along the rivers, supported by the growing agricultural developments.[7] By 1910, cotton plants were estimated to occupy nearly one-fifth of Turkestan's arable land, with about one half located in the Fergana Valley.[10]
In Iraq the only reported Caspian tiger was killed near Mosul in 1887.[11] The last known tiger in the Causasus region was killed in 1922 near Tbilisi, Georgia, after taking domestic livestock. They disappeared from the Tarim River basin in Xinjiang in the 1920s.[12][13] In Kazakhstan the last tiger as recorded in 1948 in the environs of the Ili River, their last stronghold in the region of Lake Balkhash.[4] In Turkmenistan the last tiger was killed in January 1954 in the valley of the Sumbar River in the Kopet-Dag Range.[14] In Iran's Golestān Province one of the last tigers was shot in 1953; one individual was sighted in the area in 1958.[15] In the Tian Shan mountains west of Ürümqi in China, the last Caspian tigers disappeared from the Manasi River basin in the 1960s. The last record from the lower reaches of the Amu-Darya river near the Aral Sea was an unconfirmed observation near Nukus in 1968. By the early 1970s, tigers disappeared from the river’s lower reaches and the Pyzandh Valley in the Turkmen-Uzbek-Afghan border region.[4]
There are claims of a documented killing of a tiger at Uludere, Hakkari in Turkey in 1970.[16][17] Questionnaire surveys conducted in southeastern Turkey revealed that one to eight tigers were killed each year in eastern Turkey until the mid 1980s, and that tigers likely had survived in the region until the early 1990s. Due to lack of interest in addition to security and safety reasons, no further field surveys were carried out in the area.[17]
In 1938, the first protected area Tigrovaya Balka, “tiger former river channel”, was established in Tajikistan. The name was given to this zapovednik after a tiger had attacked two Russian Army officers riding horseback along a dried-up river channel called balka. Tigrovaya Balka was the last stronghold of Caspian tigers in the Soviet Union, and is situated in the lower reaches of Vakhsh River between the Piandj and Kofarnihon River near the border of Afghanistan. The last Caspian tiger was seen there in 1958.[18]
Since 1947, tigers were legally protected in the USSR.[7]
In Iran Caspian tigers have been protected since 1957, with heavy fines for shooting. In the early 1970s, biologists from the Iran Department of the Environment searched several years for Caspian tigers in the uninhabitated areas of Caspian forests, but did not find any evidence of their presence.[15]
Stimulated by recent findings that the Amur tiger is the closest relative of the Caspian tiger, discussions started if the Amur tiger could be an appropriate subspecies for reintroduction into a safe place in Central Asia. The Amu-Darya Delta was suggested as a potential site for such a project. A feasibility study was initiated to investigate if the area is suitable and if such an initiative would receive support from relevant decision makers. A viable tiger population of about 100 animals would require at least 5,000 km2 (1,900 sq mi) of large tracts of contiguous habitat with rich prey populations. Such habitat is not available at this stage and can not be provided in the short term. The proposed region is therefore unsuitable for the reintroduction, at least at this stage of developments.[7]