Sunday, April 25, 2010
Tuesday, April 20, 2010
In an incident at the San Francisco Zoo on 25 December 2007, a Siberian tiger named Tatiana escaped and killed one visitor, injuring two others. The animal was shot dead by the police. The zoo was widely criticized for maintaining only a 12½ ft (3.8m) fence around the tiger enclosure, while the international standard is 16 ft. (4.8m). The zoo subsequently erected a taller barrier topped by an electric fence. The police say that one of the victims admitted to taunting the animal.
Thursday, April 15, 2010
The large, distinctive and powerful cats are popular zoo exhibits. The Siberian tiger is bred under the auspices of the Species Survival Plan (SSP), in a project based on 83 tigers captured in the wild. According to most experts, this population is large enough to stay stable and genetically healthy. Today, approximately 160 Siberian tigers participate in the SSP, which makes it the most extensively bred tiger subspecies within the program. There are currently no more than around 255 tigers in the tiger SSP from three different subspecies. Developed in 1982, the Species Survival Plan for the Siberian tiger is the longest running program for a tiger subspecies. It has been very fortunate and productive, and the breeding program for the Siberian tiger has actually been used as a good example when new programs have been designed to save other animal species from extinction.
The Siberian tiger is not very difficult to breed in captivity, but the possibility of survival for animals bred in captivity released into the wild is small. Conservation efforts that secure the wild population are therefore still imperative. If a captive bred Siberian tiger were to be released into the wild, it would lack the necessary hunting skills and starve to death. Captive bred tigers can also approach humans and villages, since they have learned to associate humans with feeding and lack the natural shyness of the wild tigers. In a worst-case scenario, the starving tigers could even become man-eaters. Since tigers must be taught how to hunt by their mothers when they are still cubs, a program that aimed to release captive bred Siberian tigers into the wild would create great difficulties.
Saturday, April 10, 2010
The Russian government had worked heavily to eradicate the Caspian tiger during planning a huge land reclamation program in the beginning of the 20th century. They considered there was no room for the tiger in their plans and so instructed the Russian army to exterminate all tigers found around the area of the Caspian Sea, a project that was carried out very efficiently. Once the extermination of the Caspian tiger was almost complete, the farmers cleared forests and planted crops like rice and cotton. Due to intensive hunting and deforestation, the Caspian tiger retreated first from the lush lowlands to the forested ranges, then to the marshes around some of the larger rivers, and finally, deeper into the mountains, until it almost certainly became extinct. In 1938, national park Tigrovaya Balka was opened in Tajik SSR to save Riparian forests and rare animals, including Caspian Tiger, but it didn't help the population of tigers. It was the last stronghold of the Caspian tiger in the Soviet Union. Tigrovaya Balka national park is situated in Tajikistan in the undercurrent of Vakhsh River between the Piandj and Kafirnighan near the border of Afghanistan. The last Caspian Tiger was seen there in 1958.
Some reports state that the last Caspian tiger was shot in Golestan National Park (Iran) or in Northern Iran in 1959 (Vuosalo 1976). However, other reports claim that the last Chinese Caspian tigers disappeared from the Manas River basin in the Tian Shan mountains, west of Ürümqi, China, in the 1960s. (Nowell & Jackson 1996) The last record from the lower reaches of the Amu Darya river near Lake Aral was an unconfirmed observation near Nukus in 1968 while tigers disappeared from the river’s lower reaches and the Pyzandh Valley once a stronghold, in the Turkmen-Uzbek-Afghan border region by the early 1970s (Heptner and Sludskii 1972). (Nowell & Jackson 1996) There are even claims of a documented killing of this subspecies at Uludere, Hakkari in Turkey during 1970 (Üstay 1990; Can 2004). Some reports even state that the final Caspian tiger was captured and killed in Northeast Afghanistan in 1997.
The most frequently quoted date is the late 1950s, but has almost no evidence to back it up. It appears this date came to be accepted after being quoted by H. Ziaie in "A Field Guide to the Mammals of Iran". Now, the most evidence reflects an even earlier date of extinction. The area of Iran that contained the last Caspian tigers was in fact the eastern region of Mazandaran, Northern Iran. According to E. Firouz in “A Guide to the Fauna of Iran, 1999”, the last tiger was killed in 1947 near Agh-Ghomish Village, 10 km East of Kalaleh, on the way to Minoodasht-Bojnoord. An exact date of extinction is unknown.
Monday, April 5, 2010
In the early years of the Russian Civil War, both Red and White armies based in Vladivostok nearly wiped out the local Siberian tigers. In 1935, when the Manchurian Chinese were driven back across the Amur and the Ussuri, the tigers had already withdrawn from their northern and western range. The few that remained in the East Manchurian mountains were cut off from the main population by the building of railroads. Within a few years, the last viable Siberian tiger population was confined to Ussuriland. Legal tiger hunting within the Soviet Union would continue until 1947 when it was officially prohibited. In 1962, the last tiger in Heilongjiang received protection. In the mid 1980s, it was estimated that the Siberian tiger population consisted of approximately 250 animals.
In 1987, law and order almost entirely broke down due to the impending collapse of the Soviet Union. Subsequent illegal deforestation and bribery of park rangers made the poaching of Siberian tigers easier, once again putting the subspecies at risk from extinction. However due to the work of The Siberian Tiger Project, founded in 1992, the Siberian tiger has seen a steady recovery and stabilization after the disastrous post-Soviet years that saw its numbers decline sharply. The basis of the success has largely been on the meticulous research carried out on these tigers which led to the longest ongoing study of a single tiger, Olga Project Tiger #1. Through this the project was able to focus their conservation efforts to decrease tiger mortality and to improve the quality of their habitat as well. The project included anti-poaching patrols, consultation with local governments regarding human-tiger conflicts, reducing the occurrences of clearcut logging, and other habitat depletion activities.
Thursday, April 1, 2010
In areas where wolves and tigers share ranges, the two species typically display a great deal of dietary overlap, resulting in intense competition. Wolf and tiger interactions are well documented in Sikhote-Alin, which until the beginning of the 20th century, held very few wolves. It is thought by certain experts that wolf numbers increased in the region after tigers were largely eliminated during the Russian colonization in the late 1800s and early 1900s. This is corroborated by native inhabitants of the region claiming that they had no memory of wolves inhabiting Sikhote-Alin until the 1930s, when tiger numbers decreased. Tigers depress wolf numbers, either to the point of localized extinction or to such low numbers as to make them a functionally insignificant component of the ecosystem. Wolves appear capable of escaping competitive exclusion from tigers only when human pressure decreases tiger numbers. Today wolves are considered scarce in tiger inhabited areas, being found in scattered pockets, and usually seen travelling as loners or in small groups. First hand accounts on interactions between the two species indicate that tigers occasionally chase wolves from their kills, while wolves will scavenge from tiger kills. Tigers are not known to prey on wolves, though there are four records of tigers killing wolves without consuming them. This competitive exclusion of wolves by tigers has been used by Russian conservationists to convince hunters in the Far East to tolerate the big cats, as they limit ungulate populations less than wolves, and are effective in controlling wolf numbers.