A dove flies with a coloured leaf in Ravensburg, southern Germany, on October 13, 2015. (Photo by Felix Kaestle/AFP Photo)





A keeper holds a four-week-old jaguar while presenting it to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)





A couple of four-week-old jaguars are pictured as they are presented to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)





A keeper feeds a four-week-old jaguar while presenting it to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)





A keeper holds a four-week-old jaguar while presenting it to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)





A couple of four-week-old jaguars are pictured as they are presented to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)





A keeper feeds a four-week-old jaguar while presenting it to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)





An elk runs in a field during a frosty autumn morning near the village of Astanovka, north of Minsk, in the remote corner of Belarus, October 16, 2015. (Photo by Vasily Fedosenko/Reuters)





A female Patagonian Mara cosies up her newly born offspring at ZSL Whipsnade Zoo on October 13, 2015 in Whipsnade, England. Mara breed all year round and are used to extremes of weather. (Photo by Tony Margiocchi/Barcroft Media)





A panther chameleon (Furcifer pardalis) at the Ueno Zoological Gardens in Tokyo, Japan, 04 October 2015. The Ueno Zoological Gardens is the oldest zoo in Japan. Founded in 1882, it is now home to over 3,000 animals from some 400 different species. (Photo by Franck Robichon/EPA)





A handout picture made available by Australia's Taronga Zoo shows an orphaned Brushtail Possum joey nicknamed 'Bettina' at Taronga Zoo in Sydney, 06 October 2015. Zoo keeper Felicity Evans has taken on the role of surrogate mother to the four-month-old possum, carrying a makeshift pouch and waking in the middle of the night to bottle feed and toilet the joey. (EPA/Taronga Zoo)





A Filipino holds a baby Humboldt penguin inside an aquarium at the Manila Ocean Park, in Manila, Philippines, 06 October 2015. Two new penguin hatchlings were hatched last August under the care of the Manila Ocean Park's curatorial team. The penguins are still being fed by the parents and will be ready for hand-feeding when the babies reach the weight of at least three kilos, a penguin expert said. (Photo by Mark R. Cristino/EPA)





A young lion is disciplined by his father in Basel zoo, Switzerland, 14 October 2015. Zoo Basel supports the Big Life Foundation, which works in the Amboseli-Tsavo ecosystem in Kenya to protect the Lions. The Zoo is also a participant in the EAZA Endangered Species Breeding Programme for African Lions. (Photo by Georgios Kefalas/EPA)





A trainer holds a three-week-old albinos turtle Boettgeri next to an adult turtle at the Turtle Valley animal park in Sorede on October 13, 2015. (Photo by Raymond Roig/AFP Photo)





This undated handout photograph released by The World Wildlife Foundation on October 6, 2015, shows a blue snakehead fish at an undisclosed location in the eastern Himalayas. A monkey that sneezes when it rains and a "walking" fish are among more than 200 species discovered in the fragile eastern Himalayas in recent years, according to conservation group WWF. WWF has compiled a survey of wildlife discovered by scientists across Bhutan, northeast India, Nepal, north Myanmar and southern Tibet in a bid to raise awareness of the threats facing the ecologically sensitive region. (Photo by Henning Strack Hansen/AFP Photo/WWF)





Walrus baby "Loki" relaxes next to her mother Polosa in the Hagenbeck zoo, Hamburg, northern Germany on October 13, 2015. The animal, born on June 5 weighs 111 kg was baptized on Tuesday. (Photo by Christian Charisius/AFP Photo/DPA)





A young lion snarls in Basel zoo, Switzerland, October 14, 2015. Zoo Basel supports the Big Life Foundation, which works in the Amboseli-Tsavo ecosystem in Kenya to protect the Lions. The Zoo is also a participant in the EAZA Endangered Species Breeding Programme for African Lions. (Photo by Georgios Kefalas/EPA)





Drill monkey baby Pinto plays in the enclosure at the zoo Hellabrunn in Munich, southern Germany on July 22, 2015. The male monkey was born on June 24, 2015 at the zoo and is the third baby of 10 year-old Kaduna. (Photo by Christof Stache/AFP Photo)





A bear stands on a pumpkin at the Detroit Zoo on Wednesday, October 14, 2015 in Royal Oak, Mich. (Photo by Tanya Moutzalias/MLive Detroit via AP Photo)





Chimps share a pumpkin during Smashing Pumpkins at the Detroit Zoo, Wednesday, October 14, 2015, in Royal Oak, Mich. The event is part of the zoo's "comprehensive program of ensuring environments for animals that are ever changing and appropriately complex", according to zoo officials. (Photo by Todd McInturf/The Detroit News via AP Photo)





Two jaguarundi (Puma yagouaroundi) cubs play at the National Zoo of El Salvador in San Salvador, on October 9, 2015. Three-month cubs were recovered by the National Civil Police when hunters killed a puppy and the mother. (Photo by Marvin Recinos/AFP Photo)





In this photo taken Tuesday, October 13, 2015, Karen the goat eats blackberry bushes at Minto-Brown Island Park in Salem, Ore. Salem Parks has contracted with Yoder Goat Rentals for a pilot vegetation removal project at the park. The goats will be targeting invasive plant species such as blackberry and English ivy. (Photo by Ashley Smith/Statesman-Journal via AP Photo)





A circus employee pets an elephant during an advertising display in a park in Bucharest, Romania, Wednesday, October 14, 2015. Dozens gathered to watch the show preview which showcased acrobats and trained animals. (Photo by Vadim Ghirda/AP Photo)