Gentoo penguins begin the breeding season at Edinburgh Zoo on March 1, 2011 in Edinburgh, Scotland. The zoo keepers have just installed the nest rings in the penguin enclosure. The male penguins will then collect pebbles and offer them to the females to fill nest rings with, this helps keep the eggs and chick up off the ground and is part of their courtship display. (Photo by Jeff J Mitchell/Getty Images)ю EDINBURGH, SCOTLAND – MARCH 01

Three-month old cheetah cubs make their public debut at the Smithsonian National Zoo on July 24, 2012 in Washington, DC. (Photo by T.J. Kirkpatrick)

Residents (R to L) Luiza, Janubie, Leiticia and Lucas sit beneath an overpass near their houses in an impoverished area in the unpacified Complexo da Mare slum complex, one of the largest “favela” complexes in Rio, on March 18, 2014 in Rio de Janeiro, Brazil. (Photo by Mario Tama/Getty Images)

Employees conduct a final check to fix any cavities in the seams of balls inside the soccer ball factory that produces official match balls for the 2014 World Cup in Brazil, in Sialkot, Punjab province May 16, 2014. It was when he felt the roar of the crowd at the 2006 World Cup in Germany that Pakistani factory owner Khawaja Akhtar first dreamt up a goal of his own: to manufacture the ball for the biggest soccer tournament on the planet. Last year he finally got his chance – but only 33 days to make it happen. (Photo by Sara Farid/Reuters)

Bao Bao, the Giant Panda cub is seen by the media for the first time January 6, 2014 inside his glass enclosure at the Smithsonian's National Zoo in Washington, DC, a few days before going on display to the general public. Bao Bao was born at the Smithsonian's National Zoo August 2, 2013. (Photo by Paul J. Richards/AFP Photo)

A white Bengal tiger cub born in captivity is seen during a press presentation at Huachipa's private zoo in Lima, Peru, March 16, 2016. (Photo by Mariana Bazo/Reuters)

Gaza authorities say two newborn lion cubs just unveiled by Hamas as prized additions in a zoo they run have died. Mohammad Abdel-Rahman, the acting manager of the Beit Lahiya zoo in northern Gaza, said Thursday the cubs died of an unspecified illness. He said the zoo's staff was unable to save them because they lacked experience in caring for newborn cubs. Photo: Two-day-old lion cubs Fajr and Sjel are fed at a zoo in the northern Gaza Strip town of Beit Lahia, on November 19, 2013. (Photo by Mohammed Abed/AFP Photo)

An orangutan named “Pacquiao” dressed in a Santa Claus costume reacts as he joins an “Animal Christmas Party” at the Malabon zoo in suburban Malabon, north of Manila, Philippines Monday, December 21, 2015. The Malabon Zoo is one of the largest private collections of exotic and endemic animals in the Philippines. (Photo by Aaron Favila/AP Photo)