Flamingos in their enclosure at Cologne Zoo, in Cologne, Germany, August 13, 2015. (Photo by Frederico Gambarini/EPA)

Sheep were herded by a border collie, foreground, at the Irish Fair in St. Paul, Minn. on Sunday August 9, 2015. (Photo by Rachel Woolf/The Star Tribune)

This handout photo provided by Roy L. Caldwell shows a LPSO male A15 canteleve large Pacific striped octopus about to catch a shrimp. Shifting shapes, sporting mesmerizing eyes, and showing uncanny intelligence, the octopus already is an oddball of the ocean. Now biologists have re-discovered a species of that sea creature that shares some of our social and mating habits. (Photo by Roy L. Caldwell via AP Photo)

This handout photo provided by Roy L. Caldwell shows a small male larger Pacific striped octopus stalking its prey. Shifting shapes, sporting mesmerizing eyes, and showing uncanny intelligence, the octopus already is an oddball of the ocean. Now biologists have re-discovered a species of that sea creature that shares some of our social and mating habits. (Photo by Roy L. Caldwell via AP Photo)

Five chimpanzees eat icecream made of yogurt and fruits during sunny weather at the Serengeti Park in Hodenhagen, northern Germany, Sunday, August 9, 2015. (Photo by Peter Steffen/DPA via AP Photo)

Zebras tussle in Amboseli National park, Kenya, August 9, 2015. (Photo by Goran Tomasevic/Reuters)

Pelicans fish in a swamp in Amboseli National park, Kenya, August 9, 2015. (Photo by Goran Tomasevic/Reuters)

Pelicans catch a fish in a swamp in Amboseli National park, Kenya, August 9, 2015. (Photo by Goran Tomasevic/Reuters)

Pelicans fish in a swamp in Amboseli National park, Kenya, August 9, 2015. (Photo by Goran Tomasevic/Reuters)

Pelicans catch a fish in a swamp in Amboseli National park, Kenya, August 9, 2015. (Photo by Goran Tomasevic/Reuters)

Giant Panda Mei Xiang snacks on bamboo at the Snithsonian's National Zoo in Washington, in this handout image taken on April 19, 2015 and obtained on August 10, 2015. The National Zoo's giant panda Mei Xiang is showing signs of being pregnant, the Washington zoo said on Monday, in a good development for the endangered species. (Photo by Connor Mallon/Reuters/Smithsonian's National Zoo)

Giant panda Mei Xiang plays inside the Snithsonian's National Zoo in Washington, in this handout image taken on April 19, 2015 and obtained on August 10, 2015. (Photo by Connor Mallon/Reuters/Smithsonian's National Zoo)

Giant panda Mei Xiang sleeps indoors at Smithsonian's National Zoological Park in Washington, DC, USA, 11 August 2015. Scientists have confirmed a secondary rise in giant panda Mei Xiang's urinary progesterone levels. The rise started 20 July and indicates that she will either have a cub or experience the end of a pseudopregnancy within 30 to 50 days. Mei Xiang was artificially inseminated in late April, with frozen sperm collected from Hui Hui, a panda living in China, and fresh sperm collected from the National Zoo's Tian Tian. (Photo by Michael Reynolds/EPA)

A black bear stands in a wooded area in Newton, New Jersey, July 12, 2015. New Jersey, the U.S. State most densely populated by humans, is also thick with black bears, and wildlife officials are set to vote on August 11, 2015 on a plan to expand hunting season months after the state's first fatal attack. (Photo by Barbara Goldberg/Reuters)

4-week-old elephant Anjuli cuddles with his brother Assam in Hagenbeck Zoo in Hamburg, northern Germany August 12, 2015. (Photo by Fabian Bimmer/Reuters)

Four-week-old elephant Anjuli cuddles with his brother Assam in Hagenbeck Zoo in Hamburg, northern Germany August 12, 2015. (Photo by Fabian Bimmer/Reuters)

Four-week-old elephant Anjuli plays in the sand in Hagenbeck Zoo in Hamburg, northern Germany August 12, 2015. (Photo by Fabian Bimmer/Reuters)

Four-week-old elephant Anjuli plays in the sand in Hagenbeck Zoo in Hamburg, northern Germany August 12, 2015. (Photo by Fabian Bimmer/Reuters)

Four-week-old elephant Anjuli plays in the sand in Hagenbeck Zoo in Hamburg, northern Germany August 12, 2015. (Photo by Fabian Bimmer/Reuters)

A mahout plays with an elephant at the Hanoi Zoo in Hanoi, Vietnam, 10 August 2015. The elephants at Hanoi Zoo have been unchained at the ankles after having spent most of their lives constrained by them, according to Animals Asia Foundation (AAF). World Elephant Day is marked on 12 August 2015. (Photo by Minh Hoang/EPA)

Sita, an Indian Elephant cools off in its enclosure at the zoo in Prague, Czech republic, 12 August 2015. World Elephant Day is marked on 12 August, to raise awareness of threats to Asian and African elephants. (Photo by Filip Singer/EPA)

Two baby elephants cool off in a small pool at the Royal Elephant Kraal in the ancient historical city of Ayutthaya, north of Bangkok, Thailand, 11 August 2015. The Royal Elephant Kraal is one of Thailand's best homes for elephants with as many as 65 baby elephants born since opening 20 years ago, and home to a total of over 200 elephants. The World elephant day is celebrated on 12 August, dedicated to the preservation and protection of elephants worldwide. (Photo by Diego Azubel/EPA)

Mahouts sit on top of elephants as they wait for tourists at the Ayutthaya Elephant Palace in the ancient historical city of Ayutthaya, north of Bangkok, Thailand, 11 August 2015. (Photo by Diego Azubel/EPA)

Forty One year old Elephant “Maali” is fed by a zoo keeper inside an enclosure at the Manila Zoo, Philippines, 11 August 2015. (Photo by Diego Azubel/EPA)

Barny, the Harveys Brewery dog has a sniff of a pint of beer at the Great British Beer Festival, at Olympia in London, Tuesday, August 11, 2015. The five day event is organised by the Campaign for Real Ale (CAMRA), with over 900 real ales, ciders, perries and international beers on offer. (Photo by Kirsty Wigglesworth/AP Photo)

A veterinarian handles two new born Bengal tiger cubs at Bali Zoo on August 12, 2015 in Gianyar, Bali, Indonesia. The Bengal tiger cubs were born on Sunday, August, 2 2015 in Bali Zoo. (Photo by Putu Sayoga/Getty Images)

A ten day old Bengal Tiger cub is carried by his mother in the Bali Zoo in Gianyar, Bali, Indonesia, August 12, 2015. Dewa and Dewi are two Bengal Tiger cubs who were born on August 2, 2015 from the pair of Bengal Tigers Kartini and King in the Bali Zoo. (Photo by Made Nagi/EPA)

A new born Bengal tiger cub is seen at Bali Zoo on August 12, 2015 in Gianyar, Bali, Indonesia. (Photo by Putu Sayoga/Getty Images)

A veterinarian measures the weight of the new born Bengal tiger cub at Bali Zoo on August 12, 2015 in Gianyar, Bali, Indonesia. (Photo by Putu Sayoga/Getty Images)

A veterinarian handles a new born Bengal tiger cub at Bali Zoo on August 12, 2015 in Gianyar, Bali, Indonesia. (Photo by Putu Sayoga/Getty Images)

A new born Bengal tiger cub is seen at Bali Zoo on August 12, 2015 in Gianyar, Bali, Indonesia. (Photo by Putu Sayoga/Getty Images)

Two new born Bengal tiger cubs are seen at Bali Zoo on August 12, 2015 in Gianyar, Bali, Indonesia. (Photo by Putu Sayoga/Getty Images)

Snow leopard mother Siri stands next to her male cub Barid on August 13, 2015 at the zoo in Cologne, western Germany. Barid, whose name means “cloud” in Tibetan language, was born at the zoo on May 8, 2015. (Photo by Federico Gambarini/AFP Photo/DPA)

A photo taken on August 10, 2015 shows a family of Guinea Baboons standing on a rock at the Paris Zoological Park (parc zoologique de Paris), formerly known as the Bois de Vincennes Zoological Park, in Paris. The zoo reopened to the public on April 12, after 6 years of renovation work. (Photo by Bertrand Guay/AFP Photo)

A gorilla is seen inside its enclosure at Loro Parque in Tenerife, Spain, 13 August 2015. La Laguna University and Loro Parque Foundation are conducting studies on gorillas in order determine if they are capable of reaching certain goals without any previous learning. (Photo by Cristobal Garcia/EPA)