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 

One of three newborn white Bengal tiger cubs is pictured with its mother in La Pastora Zoo in the municipality of Guadalupe, Mexico April 25, 2019. REUTERS/Daniel Becerril TPX IMAGES OF THE DAY 

Three newborn white Bengal tiger cubs are pictured with their mother in La Pastora Zoo in the municipality of Guadalupe, Mexico April 25, 2019. REUTERS/Daniel Becerril 

Three newborn white Bengal tiger cubs are pictured with their mother in La Pastora Zoo in the municipality of Guadalupe, Mexico April 25, 2019. REUTERS/Daniel Becerril 

A two-month old Bengal tiger cub is seen with the mother at Huachipa zoo in Lima, Peru October 30, 2018 REUTERS/Mariana Bazo 

Harau, a 3-year-old male Sumatran tiger (Panthera tigris sumatrae), looks on in his enclosure at Bioparc Fuengirola in Fuengirola, near Malaga, southern Spain, June 12, 2018. REUTERS/Jon Nazca 

Newborn white Bengal tiger cubs are shown to the media at San Jorge zoo in Ciudad Juarez, Mexico, November 28, 2017. REUTERS/Jose Luis Gonzalez TPX IMAGES OF THE DAY 

Asmara, a female sumatran tiger (Panthera tigris sumatrae), walks in her enclosure at Bioparc Fuengirola in Fuengirola, near Malaga, southern Spain, February 8, 2017. REUTERS/Jon Nazca 

A white Bengal tiger cub plays with its sister, a golden Bengal tiger cub, at the Circo de Renato (Renato Circus) in Ciudad Sandino, Nicaragua April 6, 2016. Picture taken April 6. REUTERS/Oswaldo Rivas TPX IMAGES OF THE DAY

Terima, a Sumatran tiger enjoys the sunshine at Manor House Wildlife Park in Tenby, Wales November 2, 2015. Wales has been enjoying record temperatures for the month of November, local media reported. REUTERS/Rebecca Naden 

Terima, a Sumatran tiger enjoys the sunshine at Manor House Wildlife Park in Tenby, Wales November 2, 2015. Wales has been enjoying record temperatures for the month of November, local media reported. REUTERS/Rebecca Naden 

Terima, a Sumatran tiger enjoys the sunshine at Manor House Wildlife Park in Tenby, Wales November 2, 2015. Wales has been enjoying record temperatures for the month of November, local media reported. REUTERS/Rebecca Naden 

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

A keeper holds a 12 week old Sumatran tiger cub during a routine health check in its enclosure at Chester Zoo in Chester northern England March 27 , 2015. The cub, one of 3 born at the zoo, was sexed, vaccinated and micro-chipped. REUTERS/Phil Noble TPX TOP IMAGES OF THE DAY 

Sumatran tiger Melati looks inside a present box put out to celebrate the first birthday of her cub triplets in their enclosure at London Zoo in London, February 4, 2015. The Zoo left gifts for the cubs in their enclosure, but they were afraid to approach the boxes, leaving their mother to enjoy their contents. REUTERS/Stefan Wermuth (BRITAIN - Tags: ANIMALS ENVIRONMENT TPX IMAGES OF THE DAY) 

Sumatran tiger cubs and their parents walk around their enclosure at London Zoo in London, January 5, 2015. The annual stock take and animal count, a requirement of London Zoo's license, included additions to the international conservation breeding programme such as the three tiger cubs and Philippine crocodiles. REUTERS/Toby Melville (BRITAIN - Tags: ANIMALS TPX IMAGES OF THE DAY) 

Bengal tigers play in a pool of water at the zoo in Malabon, Metro Manila, July 11, 2014. REUTERS/Erik De Castro (PHILIPPINES - Tags: SOCIETY ANIMALS) 

Bengal tigers play in a pool of water at the zoo in Malabon, Metro Manila, July 11, 2014. REUTERS/Erik De Castro (PHILIPPINES - Tags: SOCIETY ANIMALS) 

A white Bengal tiger cub is pictured at the White Zoo in Kernhof May 26, 2014. It is one of five cubs which were born on Sunday at the private zoo in Lower Austria, two years after their mother gave birth to four cubs in 2012. REUTERS/Heinz-Peter Bader (AUSTRIA - Tags: ANIMALS TPX IMAGES OF THE DAY) 

Twenty-one month old Adelson Gannod looks at a young male Sumatran tiger while visiting the new $19.5million Tiger Trail at the San Diego Zoo Safari Park in San Diego's San Pasqual Valley May 21, 2014. The soon to open exhibit will house six tigers and features waterfall feed ponds, rocks for climbing and tall crass for catnaps. REUTERS/Mike Blake (UNITED STATES - Tags: ANIMALS SOCIETY TPX IMAGES OF THE DAY) 

Two young male Sumatran tigers play in a new $19.5 million Tiger Trail at the San Diego Zoo Safari Park in San Diego's San Pasqual Valley May 21, 2014. The soon to open exhibit will house six tigers and features waterfall feed ponds, rocks for climbing and tall crass for catnaps. REUTERS/Mike Blake (UNITED STATES - Tags: ANIMALS SOCIETY TPX IMAGES OF THE DAY) 

White Bengal tiger Clara plays with one of her three cubs during a news presentation at Huachipa's private zoo in Lima, April 29, 2014. The 2-month-old cubs, yet unnamed, were born in captivity at the park. REUTERS/Mariana Bazo (PERU - Tags: SOCIETY ANIMALS) 

A three-month-old Bengal white tiger cub is seen inside its enclosure at the Buenos Aires' Zoo April 16, 2014. REUTERS/Enrique Marcarian (ARGENTINA - Tags: ANIMALS TPX IMAGES OF THE DAY) 

Civa Sumac, a white Bengal tiger, plays in her new enclosure during a media presentation at Huachipa's private zoo in Lima April 3, 2014. The nine-month-old tiger was born at the zoo and is the first white Bengal tiger in Peru born in captivity. REUTERS/Mariana Bazo (PERU - Tags: SOCIETY ANIMALS) 

Britain's Prince William and his father Prince Charles look at "Jae Jae", a Sumatran Tiger during their visit to the Zoological Society of London November 26, 2013. REUTERS/Eddie Mulholland/pool (BRITAIN - Tags: ROYALS ENTERTAINMENT SOCIETY ANIMALS) 

Male Sumatran tiger cub Bandar is tossed into a moat by Smithsonian National Zoo curator of great cats and bears Craig Saffoe (R) to perform in a swim test for the animal in Washington November 6, 2013. Two Sumatran tiger cubs born August 5 were tested today to have the ability to keep their heads above water, navigate the shallow end of the moat, and possess the strength and ability to climb onto dry land. REUTERS/Gary Cameron (UNITED STATES - Tags: ANIMALS ENVIRONMENT) 

Three Bengal tiger cubs play with a camera at Taman Safari Indonesia in Pasuruan, East Java province August 29, 2013. The zookeepers have to feed the three female cubs, born on July 5, 2013, as their mother has stopped giving them milk, reported local media. REUTERS/Sigit Pamungkas (INDONESIA - Tags: SOCIETY ANIMALS) 

Keeper Paul Kybett dangles a piece of meat to entice Jae Jae, a Sumatran tiger, to jump up next to a height chart during a photocall to publicize the annual measuring of all the animals at the London Zoo, in central London August 21, 2013. REUTERS/Suzanne Plunkett (BRITAIN - Tags: SOCIETY ANIMALS ENVIRONMENT) 

A white Bengal tiger cub plays with a cameraman during a press presentation at Huachipa's private zoo in Lima August 5, 2013. The 41-day-old, yet unnamed cub was born at the park and is the first white Bengal tiger in Peru to have been born in captivity. REUTERS/Mariana Bazo (PERU - Tags: ANIMALS SOCIETY) 

A white Bengal tiger cub plays with a journalist during a press presentation at Huachipa's private zoo in Lima August 5, 2013. The 41-day-old, yet unnamed cub was born at the park and is the first white Bengal tiger in Peru to have been born in captivity. REUTERS/Mariana Bazo (PERU - Tags: ANIMALS SOCIETY) 

Kirana, a female Sumatran tiger nuzzles one of her month-old cubs in their enclosure at Chester Zoo in northern England July 1, 2013. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS) 

Alternative medicine specialist Mor Mosinzon (L) treats Pedang, a 14-year-old male Sumatran tiger suffering from a chronic ear infection, with acupuncture at the Ramat Gan Safari near Tel Aviv June 9, 2013. Anesthetized twice in the past to treat its ailment, Pedang underwent acupuncture for the first time on Sunday in hope of solving the problem, the safari said in a statement. REUTERS/Nir Elias (ISRAEL - Tags: ANIMALS HEALTH SOCIETY) 

A two- month old Bengal tiger cub reacts in its enclosure at the animal refuge La Fundacion Refugio Salvaje (Furesa) in La Libertad on the outskirts of San Salvador May 23, 2013. The refuges takes care of animals in danger of extinction. REUTERS/Ulises Rodriguez (EL SALVADOR - Tags: ANIMALS) 

A two- months old Bengal tiger cub yawns while in its enclosure at the animal refuge La Fundacion Refugio Salvaje (Furesa) in La Libertad on the outskirts of San Salvador May 23, 2013. The refuges takes care of animals in danger of extinction. REUTERS/Ulises Rodriguez (EL SALVADOR - Tags: ANIMALS) 

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 Bengal tiger is staged for the late show for the Cole Brothers Circus of the Stars during its stop in Myrtle Beach, South Carolina March 31, 2013. Traveling circuses such as the Cole Brothers Circus of the Stars, complete with its big top tent, set up their tent city in smaller markets all along the East Coast of the United States as they aim to bring the circus to rural areas. The Cole Brothers Circus, now in its 129th edition, travels to 100 cities in 20-25 states and stages 250 shows a year. REUTERS/Randall Hill (UNITED STATES - Tags: SOCIETY ENTERTAINMENT ANIMALS)

White Bengal tigers are staged for the early show for the Cole Brothers Circus of the Stars during its stop in Myrtle Beach, South Carolina March 31, 2013. Traveling circuses such as the Cole Brothers Circus of the Stars, complete with its big top tent, set up their tent city in smaller markets all along the East Coast of the United States as they aim to bring the circus to rural areas. The Cole Brothers Circus, now in its 129th edition, travels to 100 cities in 20-25 states and stages 250 shows a year. Picture taken March 31, 2013. REUTERS/Randall Hill (UNITED STATES - Tags: SOCIETY ENTERTAINMENT ANIMALS) 

Melati (L), a four year old Sumatran Tiger and Jae Jae, her five year old male companion, face off in their new 2,500 square meter enclosure at London Zoo March 22, 2013. The zoo hopes that Melati and Jae Jae, will breed in captivity. REUTERS/Andrew Winning (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY) 

Melati (R), a four year old Sumatran Tiger and Jae Jae, her five year old male companion, face off in their new 2,500 square meter enclosure at London Zoo March 22, 2013. The zoo hopes that Melati and Jae Jae, will breed in captivity. REUTERS/Andrew Winning (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY) 

Jae Jae, a five year old Sumatran Tiger, sits in his new 2,500 square meter enclosure at London Zoo March 22, 2013. The zoo hopes that Jae Jae, and his female companion Melati, will breed in captivity. REUTERS/Andrew Winning (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY) 

Jae Jae, a five year old Sumatran Tiger, looks out of his new 2,500 square meter enclosure at London Zoo March 22, 2013. The zoo hopes that Jae Jae, and his female companion Melati, will breed in captivity. REUTERS/Andrew Winning (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY) 

Four-year-old bengal tiger "Mulan Jamila" plays with keeper Soleh at Al Khaffah Islamic school in Malang, Indonesia's East Java province March 19, 2013. The tiger, a gift from a friend, is kept as a pet at the school under a government permit, according to the school. Soleh has fed the tiger 5 kg (11 lbs) of meat per day since the animal was three months old. Picture taken March 19, 2013. REUTERS/Sigit Pamungkas (INDONESIA - Tags: SOCIETY ANIMALS TPX IMAGES OF THE DAY) 

Four-year-old bengal tiger "Mulan Jamila" plays with keeper Soleh at Al Khaffah Islamic school in Malang, Indonesia's East Java province March 19, 2013. The tiger, a gift from a friend, is kept as a pet at the school under a government permit, according to the school. Soleh has fed the tiger 5 kg (11 lbs) of meat per day since the animal was three months old. Picture taken March 19, 2013. REUTERS/Sigit Pamungkas (INDONESIA - Tags: SOCIETY ANIMALS TPX IMAGES OF THE DAY) 

Khan, a 3-year-old male Bengali white tiger, rests during his weekly training session inside an open-air cage at the Royev Ruchey zoo in a suburb of Russia's Siberian city of Krasnoyarsk, February 27, 2013. Every Wednesday, a zookeeper will train Khan using meat suspended on a chain so that the tiger will not lose motor and mental skills associated with hunting, an official representative of the zoo said. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS SOCIETY) 

A Sumatran tiger plays with a pig before killing it at the Sumatra Tiger Rescue Centre compound, inside the Tambling Wildlife Nature Conservation (TWNC) near Bandar Lampung, the southern tip of Sumatra island February 24, 2013. The rescue centre has released five tigers since 2009 on the 45,000 hectares of the TWNC jungle while eight are still under their care. One of the eight will be released next year. Rizal, a tiger keeper, said on a monthly basis the eight tigers eat a total of 80 live pigs, each weighing between 10-12 kilograms. The Sumatran tiger is a rare tiger subspecies that inhabits the Indonesian island of Sumatra. About 440-600 Sumatran tigers, which was classified as critically endangered, were accounted for by the International Union for Conservation of Nature (IUCN) in 2008. The owner of TWNC, Tomy Winata, said his company, Artha Graha, has already invested between $20-25 million in TWNC, with monthly costs to sustain the reserve at approximately $150,000. Picture taken February 24, 2013. REUTERS/Beawiharta (INDONESIA - Tags: SOCIETY ANIMALS) 

A Sumatran tiger growls at the Sumatra Tiger Rescue Centre compound, inside the Tambling Wildlife Nature Conservation (TWNC), near Bandar Lampung, the southern tip of Sumatra island, February 25, 2013. The rescue centre has released five tigers since 2009 on the 45,000 hectares of the TWNC jungle while eight are still under their care. One of the eight will be released next year. Rizal, a tiger keeper, said on a monthly basis the eight tigers eat a total of 80 live pigs, each weighing between 10-12 kilograms. The Sumatran tiger is a rare tiger subspecies that inhabits the Indonesian island of Sumatra. About 440-600 Sumatran tigers, which was classified as critically endangered, were accounted for by the International Union for Conservation of Nature (IUCN) in 2008. The owner of TWNC, Tomy Winata, said his company, Artha Graha, has already invested between $20-25 million in TWNC, with monthly costs to sustain the reserve at approximately $150,000. Picture taken February 25, 2013. REUTERS/Beawiharta (INDONESIA - Tags: SOCIETY ANIMALS) 

Eight-week-old white tiger (Panthera tigris) cubs are seen after a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

A female White tiger (Panthera tigris) named Shilang and her cubs are seen after a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. The three white tiger cubs, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

An eight-week-old white tiger (Panthera tigris) cub growls after a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

Eight-week-old white tiger (Panthera tigris) cubs are seen after a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

Eight-week-old white tiger (Panthera tigris) cubs are seen after a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

Two eight-week-old white tiger (Panthera tigris) cubs are seen after a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

Eight-week-old white tiger (Panthera tigris) cubs are held up during a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers (L-R), a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday. REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

Asira, an eight-week-old white tiger (Panthera tigris) cub, is held during a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday.  REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

Asira, an eight-week-old white tiger (Panthera tigris) cub, is weighed during a medical examination by veterinary surgeons at Bratislava Zoo February 8, 2013. Three white tigers, a male named Adzaj and two females Adisa and Asira were presented to the media for the first time on Friday.  REUTERS/Radovan Stoklasa (SLOVAKIA - Tags: ANIMALS SOCIETY) 

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) 

Two bengal tigers walk at their enclosure at the Huachipa Zoo in Lima, November 16, 2012. REUTERS/Enrique Castro-Mendivil (PERU - Tags: ENVIRONMENT ANIMALS) 

Khan, a 2-year-old male Bengali white tiger, is seen inside a cage at the Royev Ruchey zoo in Russia's Siberian city of Krasnoyarsk September 26, 2012. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS SOCIETY) 

A veterinarian examines three 20-day-old Bengal tiger cubs at Bali Zoo Park, in Gianyar, Bali resort island June 29, 2012. The Bengal tiger is a tiger subspecies native to India, classified as endangered by the International Union for Conservation of Nature (IUCN) with estimated population of less than 2,500. Picture taken June 29, 2012. REUTERS/Stringer (INDONESIA - Tags: SOCIETY ANIMALS) 

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)