Siberian tigers bathe in a pool to cool down at Al Zawra zoo in Baghdad, Iraq, June 29, 2019. Picture taken June 29, 2019. REUTERS/Thaier al-Sudani 

A Siberian tiger growls in its enclosure on a hot summer day at Prague Zoo, Czech Republic, July 30, 2015. REUTERS/David W Cerny

Bartek, a one-year-old male Amur tiger, looks out from an open-air cage at the Royev Ruchey zoo on the suburbs of Russia's Siberian city of Krasnoyarsk, May 18, 2013. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS TPX IMAGES OF THE DAY) 

A Siberian tiger eats a frozen chicken during a hot summer day at Rio de Janeiro's zoo January 9, 2013. According to a local climate institute, temperatures in Rio de Janeiro on Wednesday rose up to 35 degrees Celsius (95 degrees Fahrenheit). REUTERS/Sergio Moraes (BRAZIL - Tags: ANIMALS SOCIETY ENVIRONMENT) 

A Siberian tiger cub feeds at a private zoo in Abony, east of Budapest May 17, 2012. Three female Siberian cubs were born near Hamburg in Germany, but came to Hungary when they were only two and a half weeks old, after their mother became ill and could not feed them any more. They are six weeks old now and growing fast, fed on goats' milk and special tiger food. To match Reuters Life! HUNGARY-TIGERS/ Picture taken May 17, 2012. REUTERS/Stringer (HUNGARY - Tags: ANIMALS SOCIETY TPX IMAGES OF THE DAY) 

Siberian tiger cubs play at a private zoo in Abony, east of Budapest May 17, 2012. The cubs were born near Hamburg in Germany, but came to Hungary when they were only two and a half weeks old, after their mother became ill and could not feed them any more. They are six weeks old now and growing fast, fed on goats' milk and special tiger food. To match Reuters Life! HUNGARY-TIGERS/ Picture taken May 17, 2012. REUTERS/Stringer (HUNGARY - Tags: ANIMALS SOCIETY) 

Siberian tigers play in the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT) 

An 18-month-old Siberian tiger plays in the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT) 

Siberian tigers approach a keeper's car as they wait to be fed at the Siberian Tiger Forest Park in Harbin, Heilongjiang province December 27, 2011. More than 800 Siberian tigers are currently living in the park, which is also a breeding centre for this endangered species, local media reported. REUTERS/Sheng Li (CHINA - Tags: ANIMALS SOCIETY) 

Visitors watch from a bus as Siberian tigers try to catch a chicken at the Siberian Tiger Forest Park in Harbin, Heilongjiang province December 27, 2011. More than 800 Siberian tigers are currently living in the park, which is also a breeding centre for this endangered species, local media reported. REUTERS/Sheng Li (CHINA - Tags: ANIMALS SOCIETY) 

An employee of the Royev Ruchey zoo places a 2-month-old Siberian tiger cub into a basket to be weight in Russia's Siberian city of Krasnoyarsk, October 6, 2011. Iris, the Siberian tiger, had given birth to three cubs, according to zoo employees. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS SOCIETY) 

Female Amur tiger Iris licks its 7-week-old cub during one of their first walks in an open-air cage at the Royev Ruchey zoo in Russia's Siberian city of Krasnoyarsk September 29, 2011. Iris gave birth to three cubs in the beginning of August, according to zoo employees. The Amur tiger is an endangered species. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS) 

People take part in a procession during a festival to mark Tiger Day in Russia's far eastern city of Vladivostok September 25, 2011. The festival is dedicated to the protection of the Amur tiger, an endangered species. REUTERS/Yuri Maltsev (RUSSIA - Tags: SOCIETY ANNIVERSARY) 

Three two-day-old Siberian tigers crawl near their mother at Skopje's zoo, April 17, 2011. If one of the tigers is male, it will be named Putin, according to zoo manager Dane Kuzmanovski. Picture taken through a protective net. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS SOCIETY) 

Siberian tigers play together at the St-Felicien Wildlife zoo in St-Felicien, Quebec November 30, 2010. According to National Geographic, the wild population of Siberian tigers, also called Amur tiger, is estimated between 400 and 500 and is classified as an endangered species. REUTERS/Mathieu Belanger (CANADA - Tags: ANIMALS) 

A Siberian tiger yawns at the St-Felicien Wildlife zoo in St-Felicien, Quebec November 30, 2010. According to National Geographic, the wild population of Siberian tigers, also called Amur tiger, is estimated between 400 and 500 and is classified as an endangered species. REUTERS/Mathieu Belanger (CANADA - Tags: ANIMALS) 

A Siberian tiger growls at the St-Felicien Wildlife zoo in St-Felicien, Quebec November 30, 2010. According to National Geographic, the wild population of Siberian tigers, also called Amur tiger, is estimated between 400 and 500 and is classified as an endangered species. REUTERS/Mathieu Belanger (CANADA - Tags: ANIMALS IMAGES OF THE DAY) 

Artyom, a three-year-old Amur tiger, looks out of his enclosure at the zoo of Rostov-on Don, November 23, 2010. Russian Prime Minister Vladimir Putin will try to thrash out a deal with Asian leaders on Tuesday to double the world's wild tiger population by 2022 and save it from extinction. REUTERS/Vladimir Konstantinov (RUSSIA - Tags: ANIMALS POLITICS SOCIETY) 

Russo (background), a four-year-old male Chinese leopard, plays with Diana, a six-year-old female Amur leopard, in an open-air enclosure at the Royev Ruchey zoo in Krasnoyarsk, July, 11, 2010. The Amur leopard, also known as the Manchurian leopard, is one of the rarest felines in the world with an estimated 30 to 35 individuals remaining in the wild, according the ALTA (Amur Leopard and Tiger Alliance). The zoo is temporarily hosting Russo to reproduce with Diana. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS) 

Russo, a four-year-old male Chinese leopard, yawns while laying next to Diana, a six-year-old female Amur leopard, in an open-air enclosure at the Royev Ruchey zoo in Krasnoyarsk, July, 11, 2010. The Amur leopard, also known as the Manchurian leopard, is one of the rarest felines in the world with an estimated 30 to 35 individuals remaining in the wild, according the ALTA (Amur Leopard and Tiger Alliance). The zoo is temporarily hosting Russo to reproduce with Diana. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS) 

Diana, a six-year-old female rare Amur leopard, walks in her open-air cage at the Royev Ruchey zoo in Krasnoyarsk, July, 11, 2010. The Amur leopard (Panthera pardus orientalis), also known as the Manchurian leopard, is one of the rarest felines in the world with an estimated 30 to 35 individuals remaining in the wild, according the ALTA (the Amur Leopard and Tiger Alliance). REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS) 

Diana, a six-year-old female rare Amur leopard, yawns in her open-air cage at the Royev Ruchey zoo in Krasnoyarsk, July, 11, 2010. The Amur leopard (Panthera pardus orientalis), also known as the Manchurian leopard, is one of the rarest felines in the world with an estimated 30 to 35 individuals remaining in the wild, according the ALTA (the Amur Leopard and Tiger Alliance). REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS) 

Siberian tiger cubs are seen at the Dalian Forest Zoo in Dalian, Liaoning province February 7, 2010. China has an estimated 50 or fewer tigers left living in the wild, but efforts to stabilise one population in the bleak northeast are starting to pay off, a conservationist said on Monday. Picture taken February 7, 2010. REUTERS/Jacky Chen (CHINA - Tags: ANIMALS ANNIVERSARY) 

Vitali the Siberian tiger roams in his cage in the Calgary Zoo in Calgary, Alberta, October 5, 2009. Vitali hooked and clawed a man's arms early in the day after he jumped a fence and got too close to the tiger enclosure. The man is in serious condition in a Calgary hospital and police are investigating the incident. REUTERS/Todd Korol (CANADA ANIMALS SOCIETY) 

Vitali the Siberian tiger roams in his cage in the Calgary Zoo in Calgary, Alberta, October 5, 2009. Vitali hooked and clawed a man's arms early in the day after he jumped a fence and got too close to the tiger enclosure. The man is in serious condition in a Calgary hospital and police are investigating the incident. REUTERS/Todd Korol (CANADA ANIMALS SOCIETY) 

Vitali the Siberian tiger roams in his cage in the Calgary Zoo in Calgary, Alberta, October 5, 2009. Vitali hooked and clawed a man's arms early in the day after he jumped a fence and got too close to the tiger enclosure. The man is in serious condition in a Calgary hospital and police are investigating the incident. REUTERS/Todd Korol (CANADA ANIMALS SOCIETY) 

Five-week-old Amur tiger cubs play with each other at the Highland Wildlife Park near Kingussie, Scotland June 16, 2009. Their parents Sasha and Yuri, have now bred nine cubs in total with the last three born on May 11, 2009. Amur tigers, previously known as Siberian tigers, were renamed in the 1990's as they are now only found the Amur River valley in Russia, and no longer in Siberia, hence their new name. REUTERS/David Moir (BRITAIN ENVIRONMENT ANIMALS SOCIETY IMAGES OF THE DAY) 

Sasha, an Amur tiger, licks one of her three five-week-old cubs at the Highland Wildlife Park near Kingussie in Scotland June 16, 2009. Sasha and her partner Yuri have now bred nine cubs in total with the last three born on May 11, 2009. Amur tigers, previously known as Siberian tigers, were renamed in the 1990's as they are now only found the Amur River valley in Russia, and no longer in Siberia, hence their new name. REUTERS/David Moir (BRITAIN ENVIRONMENT ANIMALS SOCIETY) 

Sasha, an Amur tiger, carries one of her three five-week-old cubs in her mouth at the Highland Wildlife Park near Kingussie in Scotland June 16, 2009. Sasha and her partner Yuri have now bred nine cubs in total with the last three born on May 11, 2009. Amur tigers, previously known as Siberian tigers, were renamed in the 1990's as they are now only found the Amur River valley in Russia, and no longer in Siberia, hence their new name. REUTERS/David Moir (BRITAIN ENVIRONMENT ANIMALS SOCIETY IMAGES OF THE DAY) 

Koshka, a 3-year-old female Siberian tiger, growls in her enclosure at the Denver Zoo in Denver, Colorado June 12, 2009. Koshka was brought to Denver in hopes she would mate with a tiger already at the zoo. Siberian tigers are classified as critically endangered, with an estimated population of less than 400 individuals remaining in the wild. REUTERS/Rick Wilking (UNITED STATES ANIMALS SOCIETY ENVIRONMENT) 

A Siberian tiger rests at a breeding centre in Harbin, Heilongjiang province December 25, 2008. The tiger breeding centre is also a safari park where tourists can view the beasts in their natural state, local media reported. REUTERS/Sheng Li (CHINA) 

A Siberian tiger is seen at a breeding centre in Harbin, Heilongjiang province December 25, 2008. The tiger breeding centre is also a safari park where tourists can view the beasts in their natural state, local media reported. REUTERS/Sheng Li (CHINA) 

A Siberian tiger yawns at a breeding centre in Harbin, Heilongjiang province December 25, 2008. The tiger breeding centre is also a safari park where tourists can view the beasts in their natural state, local media reported. REUTERS/Sheng Li (CHINA) 

A Siberian tiger is seen at a breeding centre in Harbin, Heilongjiang province December 25, 2008. The tiger breeding centre is also a safari park where tourists can view the beasts in their natural state, local media reported. REUTERS/Sheng Li (CHINA) 

An Amur tiger (also know as a Siberian tiger) called Yuri walks in the snow in The Highland Wildlife Park in Kingussie near Aviemore, Scotland November 25, 2008. The park has two Amur tigers, which arrived from Edinburgh Zoo towards the end of September 2008. REUTERS/Russell Cheyne (BRITAIN) 

An Amur tiger (also know as a Siberian tiger) called Sasha carries a piece of meat in The Highland Wildlife Park in Kingussie near Aviemore, Scotland November 25, 2008. The park has two Amur tigers, which arrived from Edinburgh Zoo towards the end of September 2008. REUTERS/Russell Cheyne (BRITAIN) 

An Amur tiger (also know as a Siberian tiger) called Sasha eats a piece of meat in The Highland Wildlife Park in Kingussie near Aviemore, Scotland November 25, 2008. The park has two Amur tigers, which arrived from Edinburgh Zoo towards the end of September 2008. REUTERS/Russell Cheyne (BRITAIN) 

Siberian tiger mother 'Shakyra' licks one of her babies at the zoo of Hamm November 13, 2008. The birth of five tiger babies on August 13 in the zoo of Hamm was unexpected, because it was unknown that their mother 'Shakyra' was pregnant. REUTERS/ Ina Fassbender (GERMANY) 

Two three month old Siberian tiger babies play in their enclosure at the zoo of Hamm November 13, 2008. The birth of five tiger babies on August 13 in the zoo of Hamm was unexpected, because it was unknown that their mother 'Shakyra' was pregnant. REUTERS/ Ina Fassbender (GERMANY) 

Amur tigers Yuri (L) and Sasha, recently transferred from Edinburgh Zoo, are seen in their new enclosure at The Highland Wildlife Park in Kingussie, near Aviemore in Scotland October 6, 2008. With only 500 Amur tigers remaining in the wild around the Amur river valley in the far east of Russia, it is hoped that the pair will continue to contribute to the worldwide breeding programme from their new home in t5he Scottish Highlands. REUTERS/David Moir (BRITAIN) 

Sasha, a female Amur tiger, chews on a piece of meat in her new enclosure at The Highland Wildlife Park in Kingussie, near Aviemore in Scotland October 6, 2008. Sasha and her breeding partner Yuri were recently transferred from Edinburgh Zoo to their new home in the Scottish Highlands. With only 500 remaining in the wild around the Amur river valley in the far east of Russia,it is hoped that the pair will continue to contribute to the worldwide breeding programme. REUTERS/David Moir (BRITAIN) 

Sasha, a female Amur tiger, climbs a tree while looking for food in her new enclosure at The Highland Wildlife Park in Kingussie, near Aviemore in Scotland October 6, 2008. Saha and her breeding partner Yuri were recently transferred from Edinburgh Zoo to their new home in the Scottish Highlands. With only 500 remaining in the wild around the Amur river valley in the far east of Russia, it is hoped that the pair will continue to contribute to the worldwide breeding programme. REUTERS/David Moir (BRITAIN) 

Sasha, an Amur tiger, recently transported from Edinburgh Zoo, is seen in her new enclosure at The Highland Wildlife Park in Kingussie, near Aviemore in Scotland October 6, 2008. With only 500 Amur tigers remaining in the wild around the Amur river valley in the far east of Russia, it is hoped that Sasha and her partner Yuri will continue to contribute to the worldwide breeding programme from their new home in the Scottish Highlands. REUTERS/David Moir (BRITAIN) 

Yuri, a male Amur tiger, stands in front of visitors at his new enclosure at The Highland Wildlife Park in Kingussie, near Aviemore in Scotland October 6, 2008. Yuri and his breeding partner Sasha were recently transported from Edinburgh Zoo to their new home in the Scottish Highlands. With only 500 remaining in the wild around the Amur river valley in the far east of Russia, it is hoped that the pair will continue to contribute to the worldwide breeding programme. REUTERS/David Moir (BRITAIN) 

Siberian tiger 'Shakyra' lies next to one of her five two-day old cubs in her enclosure at Hamm zoo August 15, 2008. The birth of five tiger babies on Wednesday in the zoo of Hamm was unexpected, as it was unknown that 'Shakyra' was pregnant. REUTERS/ Ina Fassbender (GERMANY) 

Siberian tiger 'Shakyra' licks one of her five two-day old cubs while lying in her enclosure at Hamm zoo August 15, 2008. The birth of five tiger babies on Wednesday in the zoo of Hamm was unexpected, as it was unknown that 'Shakyra' was pregnant. REUTERS/ Ina Fassbender (GERMANY) 

Six week old Siberian tiger cub 'Antares' is presented at the Tierpark Friedrichsfelde zoo in Berlin August 4, 2008. REUTERS/Johannes Eisele (GERMANY) 

Six week old Siberian tiger cub 'Antares' is presented at the Tierpark Friedrichsfelde zoo in Berlin August 4, 2008. REUTERS/Johannes Eisele (GERMANY) 

A Siberian tiger is seen at the Hengdaohezi Siberian Tiger Zoo in Hailin, Heilongjiang province, July 15, 2008. According to the zoo, which has some 200 Siberian tigers, it is the world's largest breeding centre for Siberian tigers. Picture taken July 15, 2008. REUTERS/Patty Chen (CHINA) 

A visitor feeds meat to a Siberian tiger at the Hengdaohezi Siberian Tiger Zoo in Hailin, Heilongjiang province July 15, 2008. According to the zoo, which has some 200 Siberian tigers, it is the world's largest breeding centre for Siberian tigers. Picture taken July 15, 2008. REUTERS/Patty Chen (CHINA) 

A Siberian tiger chases a cow at the Hengdaohezi Siberian Tiger Zoo in Hailin, Heilongjiang province, July 15, 2008. According to the zoo, which has some 200 Siberian tigers, it is the world's largest breeding centre for Siberian tigers. Picture taken July 15, 2008. REUTERS/Patty Chen (CHINA) 

Siberian tigers try to catch a chicken at the Hengdaohezi Siberian Tiger Zoo in Hailin, Heilongjiang province July 15, 2008. According to the zoo, which has some 200 Siberian tigers, it is the world's largest breeding centre for Siberian tigers. Picture taken July 15, 2008. REUTERS/Patty Chen (CHINA) 

Siberian tigers try to catch a chicken at the Hengdaohezi Siberian Tiger Zoo in Hailin, Heilongjiang province, July 15, 2008. According to the zoo, which has some 200 Siberian tigers, it is the world's largest breeding centre for Siberian tigers. Picture taken July 15, 2008. REUTERS/Patty Chen (CHINA) 

A Siberian tiger eats a chicken at the Hengdaohezi Siberian Tiger Zoo in Hailin, Heilongjiang province, July 15, 2008. According to the zoo, which has some 200 Siberian tigers, it is the world's largest breeding centre for Siberian tigers. Picture taken July 15, 2008. REUTERS/Patty Chen (CHINA) 

A two-month old Amur tiger cub reacts as it plays in a cage in the municipal zoo Royev Ruchey in Russia's Siberian city of Krasnoyarsk, December 21, 2007. A pair of Amur tigers Cedar and Iris have given birth to seven cubs in the last 3 years in this zoo. REUTERS/Ilya Naymushin (RUSSIA) 

A female Amur tiger, Iris, licks her two-month old cub in a cage in the municipal zoo Royev Ruchey in Russia's Siberian city of Krasnoyarsk, December 21, 2007. A pair of Amur tigers Cedar and Iris have given birth to seven cubs in the last 3 years in the zoo. REUTERS/Ilya Naymushin (RUSSIA) 

A two-month old Amur tiger cub plays in a cage in the municipal zoo Royev Ruchey in Russia's Siberian city of Krasnoyarsk, December 21, 2007. A pair of Amur tigers Cedar and Iris have given birth to seven cubs in the last 3 years in the zoo. REUTERS/Ilya Naymushin (RUSSIA)