One of the three newborn cloud leopards go outside for the first time in Ouwehands Zoo in Rhenen, The Netherlands, July 5, 2019.

The three newborn cloud leopards gather outside for the first time at the Ouwehands Zoo in Rhenen, The Netherlands, July 5, 2019. The leopards where born on February 28, 2019 and spent four months inside in their indoor residence.

A big-eyed baby pygmy owl is seen, June 5, 2019. One of four hatched at the Phoenix Zoo three weeks ago under a special breeding program, the cactus ferruginous pygmy owls are being raised by two pairs of adult owls.

A newborn orangutan is pictured at the Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 29, 2019.

A newborn orangutan is pictured at the Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 29, 2019.

A newborn orangutan is pictured at the Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 29, 2019.

Baby ducks make their way down the hall at Prairie Mountain School on Earth Day, April 22, 2019, in Eugene, Ore., to the delight of kindergarten children gathered nearby.

A new born male elephant calf named "Gus" walks with its mother, right, in their enclosure in the Green Zoo Wuppertal, in Wuppertal, Germany, April 24, 2019.

A new born male elephant calf named "Gus" in its enclosure in the Green Zoo Wuppertal, in Wuppertal, Germany, April 24, 2019.

A one-month-old clouded leopard cub is held by a staff member of the Pittsburgh Zoo & PPG Aquarium in April 2019. A press release from the zoo says that the cub will be hand-reared because she wasn't nursing on her own.

A newly-born white lion cub, named Simba, is seen in Paphos zoo, Cyprus, April 14, 2019.

A black-and-white colobus monkey holds its 11 days old infant at its enclosure in Schoenbrunn Zoo in Vienna, Austria, April 10, 2019.

An Egyptian goose gosling stands on a meadow in Schwetzingen, Germany, March 26, 2019.

April the Giraffe with her new male calf, March 16, 2019, in Harpursville, N.Y.

April the Giraffe with her new male calf, March 16, 2019, in Harpursville, N.Y. The Animal Adventure Park said April gave birth to a healthy male calf on March 16, 2019.

A little polar bear cub and his mother Tonja walk in the outdoor enclosure of the Tierpark in Berlin, March 15,2019.

A female polar bear cub, born on December 1, 2018, is seen together with 9 year-old mother Tonja during her first official presentation for the media at Tierpark Berlin zoo in Berlin, March 15, 2019.

Newborn piglets of the so-called Bunte Bentheimer breed and their mother at the Buergerpark gardens in Bremen, northern Germany, Feb. 21, 2019.

The polar bear cub in the Copenhagen Zoo comes outside for the first time in Copenhagen, Denmark, Feb. 28, 2019.

Female gorilla Gypsy holds her 4-week-old first baby, Feb. 20, 2019, at the zoological park of Saint-Martin-la-Plaine in France.

A little female polar bear watches the camera after its first examination by the animal doctors at the zoo in Berlin, Feb. 14, 2019.

A white lion cubs in it's enclosure during their first outing at the zoo in Hodonin, Moravia, before their vaccination, Feb. 5, 2019.

Two white lion cubs in their enclosure during their first outing at the zoo in Hodonin, Moravia, before their vaccination, Feb. 5, 2019.The lion cubs were born at the end of 2018.

A five-day-old baby Rothschild giraffe is seen with her mother at the zoo in Prague, Jan. 29, 2019.

A young koala girl takes a ride on its mother Eora at the zoo in Duisburg, Germany, Jan. 17, 2019. The yet unnamed koala is almost one year old and still rides on its mother's back.

Female rhino Marcita stands with her new born cub in an enclosure at the Zoopark in Erfurt, Germany, Jan. 3, 2019. The male rhino cub was born on Dec. 29, 2018 at the zoo.

A three-day old Grevy's zebra stands by its mother in the Nyiregyhaza Animal Park in Nyiregyhaza, Budapest, Hungary, Jan. 3, 2019. Grevy's zebra is the largest species of zebras and the largest wild equid.

Vets check a baby black-furred gibbon, rescued from a villager, at the local nature conservation agency's office in Banda Aceh, Indonesia, Nov. 1, 2018.

A western lowland gorilla mother holds her baby gorilla after giving birth, Oct. 18, 2018. The western lowland gorilla lives in central Africa.

Tiger cubs Melati and Mya play in their new enclosure at the National Zoo and Aquarium in Canberra, Australia, Oct. 10, 2018.

An Atlantic seal pup lies on the rocks at St Martin's Haven, Pembrokeshire, Wales, Britain Oct. 8, 2018. Seal pups are born with fluffy white non-waterproof coats which they shed in their fourth week.

A two-week old Indian rhinoceros stands by his mother Jasmin in the Nyiregyhaza Animal Park in Nyiregyhaza, east of Budapest, Hungary, Oct. 9, 2018. The baby rhino was born on Sept. 26, 2018. He is the first of the species ever born in Hungary and the fourth one born in Europe this year.

Giant panda cubs at Chengdu Research Base of Giant Panda Breeding in Chengdu, China., Sept. 28, 2018. A total of 12 cubs born in the base in 2018 met the public.

An eight-months-old female koala cub at the zoo in Duisburg, Germany, Sept. 28,2018.

A young Cheetah with its mother at their enclosure in the zoo in Opole, Poland, Sept. 24, 2018. Three young Cheetahs were born nine weeks ago at the Zoo in Opole.

A clouded leopard cub is in a bucket during a medical exam, Sept. 17, 2018, at the Mulhouse zoo, in eastern France.

A mountain lion kitten which National Park Service researchers discovered in August 2018 in a remote area of the Santa Monica Mountains, Calif., is shown in this image released on Sept. 4, 2018.

The great one-horned rhinoceros Betty, rear, and her new born son at their enclosure at the Zoo in Berlin, Sept. 6, 2018.

A two-month-old white tiger abandoned by its mother, plays with a Golden Retriever puppy next to an African lion at Beijing Wildlife Park in Beijing, Aug. 30, 2018.

A West African dwarf crocodile hatches from its egg on Aug. 27, 2018, at the Planet Exotica zoological and botanical garden in Royan, France.

Ten-days old male cub of a Malayan tapir (Tapirus indicus) is seen in the Zlin Zoo, Czech Republic, Aug. 6, 2018.

Walrus Dyna (L) and her offspring sit in their enclosure during their first visit of the outdoor area at the Hagenbeck zoo in Hamburg, northern Germany, Aug. 3, 2018.

Baby elephants play next to their herd of elephants at Kaudulla national park in Habarana, Sri Lanka, July 30, 2018.

A giant panda, Long Long and its newborn cub at the Chimelong Safari Park in Guangzhou, capital of south China's Guangdong Province. Long Long, the first giant panda which was born in Guangdong in 2013, gave birth to a male giant cub on July 12 at the Chimelong Safari Park.

A white-nosed coati baby runs through its enclosure at the zoo in Magdeburg,Germany, July 25, 2018. Five white-nosed coati babies were born at the zoo on June 3, 2018.

Caretakers of Burgers' Zoo give two Sri Lankan leopard cubs a medical check-up, July 12, 2018, in Arnhem, Netherlands.

A baby prehensile-tailed porcupine is seen at Brookfield Zoo in Brookfield, Ill. The baby porcupine, known as a porcupette, was born at the zoo on July 2, 2018 and is being hand-reared by staff when it became clear that his mom was not providing him proper maternal care, as she was not allowing him to nurse.

Seal Shiva, right, plays with her 2 days old cub at the zoo in Berlin, July 10, 2018.

Seal Shiva plays with her 2 days old cub at the zoo in Berlin, July 10, 2018.

An adorable Barbary lion cub is seen playing at the Olomouc Zoo, Czech Republic, June 18, 2018. The cub were born to mum Lilly on May 11 and today were spotted indulging in a spot of rough and tumble before being given a thorough clean by mum Lilly. The male lion cub called Thembi which means "Hope."

An African Elephant calf is seen next to its mother, Kwanza, four hours after its birth in the Nyiregyhaza Animal Park in Nyiregyhaza, Hungary, June 16, 2018. The 17-year-old Kwanza has an older male calf named Kito, born three years prior.

An African Elephant calf is seen next to its mother, Kwanza, four hours after its birth in the Nyiregyhaza Animal Park in Nyiregyhaza, Hungary, June 16, 2018. The 17-year-old Kwanza has an older male calf named Kito, born three years prior.

An African Elephant calf is seen next to its mother, Kwanza, four hours after its birth in the Nyiregyhaza Animal Park in Nyiregyhaza, Hungary, June 16, 2018. The 17-year-old Kwanza has an older male calf named Kito, born three years prior.

The Lugdon family from Maine said on Facebook they briefly took care of a baby moose after finding it in the wild on June 9, 2018. Shannon Lugdon wrote that they followed wildlife authorities' advice to keep away from the moose for a day before returning to find that it was still alone in the same area. She said that her dog became "fast friends" with the moose, nicknamed Miss Maggie - who followed them around begging for attention. Lugdon wrote that the animal was picked up by a biologist a day later and transferred to the Maine Wildlife Park and it was estimated to be just six days old.

A zoo worker plays with a new baby panda at Malaysia Zoo in Kuala Lumpur, Malaysia, May 26, 2018. A baby panda born in a Malaysian zoo five months ago has made her first media appearance.

Three bear cubs, four months old are in an enclosure at the Belitsa bear sanctuary in Belitsa, May 24, 2018. The bears were found by the Bulgarian authorities in the wild in the Rhodope mountains and rescued from the Dancing Bears Park near the village of Belitsa.

Toy, a 10-day-old female giraffe named after Israeli singer Netta Barzilai's song "Toy", winner of the 2018 Eurovision Song Contest, is seen with its mother Laila in their pen at Jerusalem's Biblical Zoo, May 21, 2018.

Toy, a 10-day-old female giraffe named after Israeli singer Netta Barzilai's song "Toy", winner of the 2018 Eurovision Song Contest, is seen with its mother Laila in their pen at Jerusalem's Biblical Zoo, May 21, 2018.

A gosling gets on its tippy toes as it waddles with other Canada geese along the border of the river Main in Frankfurt, Germany, May 16, 2018.

One of two newborn Himalayan bear cubs, which were named Yashin and Streltsov in honor of well-known Soviet football players and Olympic champions Lev Yashin and Eduard Streltsov, is seen inside an open-air cage at the Royev Ruchey Zoo in Krasnoyarsk, Russia April 26, 2018.

An Andean bear baby looks around as it enters first time its outdoor enclosure in the zoo in Frankfurt, April 23, 2018.

A newborn Asian elephant is pictured with its mother Phyo Phyo on the first day of a public appearance at the Planckendael Zoo in Mechelen, Belgium, April 11, 2018.

A newborn Asian elephant is pictured with members of its family on the first day of a public appearance at the Planckendael Zoo in Mechelen, Belgium, April 11, 2018.

Sassafras, a newborn Koala is pictured with its mother Alinga at the Planckendael Zoo in Mechelen, Belgium, April 11, 2018.

The four-month-old okapi, named at birth after Meghan Markle in celebration of the forthcoming Royal Wedding, has started to venture out of her stable for the first time under the watchful gaze of her mum, Oni, April 5, 2018, in the ZSL London Zoo. Okapis are native to the rain forests of the Democratic Republic of Congo where the endangered species faces numerous threats, including poaching and habitat loss.

A guereza monkey (Colobus Guereza) holds a newborn baby at Prague Zoo, Czech Republic, April 5, 2018.

Baby elephant Kanja at the The wildlife park in Hamburg, Germany, March 28, 2018.

The Highland Wildlife Park female polar bear's new cub walks around their enclosure, March 20, 2018, in Kingussie, Scotland. The Royal Zoological Society of Scotland announced in January that its female polar bear, Victoria, gave birth at Highland Wildlife Park to the first cub born in the UK in 25 years.

The Highland Wildlife Park female polar bear's new cub walks around their enclosure, March 20, 2018, in Kingussie, Scotland. The Royal Zoological Society of Scotland announced in January that its female polar bear, Victoria, gave birth at Highland Wildlife Park to the first cub born in the UK in 25 years.

The Highland Wildlife Park female polar bear's new cub walks around their enclosure, March 20, 2018, in Kingussie, Scotland. The Royal Zoological Society of Scotland announced in January that its female polar bear, Victoria, gave birth at Highland Wildlife Park to the first cub born in the UK in 25 years.

Two lion cubs are seen at the Leningrad city zoo in St. Petersburg, Russia, Feb. 12, 2018.

Dashya, a 9-year-old hippopotamus, looks after her 11-day-old calf in an enclosure in the Bannerghatta Biological Park in Bangalore, India, Feb. 9, 2018.

Two Angola giraffes at the Zoo of Lisbon in Portugal, Feb. 1, 2018. The zoo has a new inhabitant, a young Angola Giraffe that was born, Nov. 16, 2017.

A 4-month-old white lion cub is presented to the press in a cage at the Altiplano Zoo in Tlaxcala, Mexico, Jan. 18, 2018.

A Bornean orang utan baby, Khansa, makes an appearance at the Singapore Zoo, Jan 11, 2018. The animals under the care of the Wildlife Reserves Singapore (WRS) gave birth to over 540 babies in 2017.