Two fourteen-week old lion cubs, a male named Ramzes and a female named Zara, are seen during a Christening ceremony at the Bojnice Zoo April 4, 2015. The two cubs are Barbary lions (Panthera leo leo), local media reported. (Photo by Radovan Stoklasa/Reuters)

“These photographs show the food chain in action as a hungry lion braved a river full of crocodiles to try and sink his teeth into a dead hippo. The photos were taken in the Maasi Mara nature reserve, in Kenya and show hungry lion braving a crocodile-infested river to get to an upside down hippo, which had died overnight of natural causes”. – Caters News. (Photo by Richard Chew/Caters News)

A “jungle nymph” is measured during the annual weight-in ZSL London Zoo on August 21, 2014 in London, England. The height and mass of every animal in the zoo, of which there are over 16,000, is recorded and submitted to the Zoological Information Management System. This is combined with animal measurement data collected from over 800 zoos and aquariums in almost 80 countries, from which zoologists can compare information on thousands of endangered species. (Photo by Oli Scarff/Getty Images)

A zoo worker feeds milk to tiger cubs born on the first day of the Lunar New Year and Year of the Rooster at Sriracha Tiger Zoo in Chonburi province, Thailand, January 30, 2017. (Photo by Athit Perawongmetha/Reuters)

A pair of giant pandas play in their enclosure at the Beijing Zoo on June 5, 2012 in Beijing, China. With an estimated 1,600 living in the wild, the endangered giant panda dwell in a few mountain ranges in central China, in Sichuan, Shaanxi, and Gansu provinces. (Photo by Lintao Zhang)

Piper Hoppe, 10, from Minnetonka, Minnesota, holds a sign at the doorway of River Bluff Dental clinic in protest against the killing of a famous lion in Zimbabwe, in Bloomington, Minnesota July 29, 2015. A Zimbabwean court on Wednesday charged a professional local hunter Theo Bronkhorst with failing to prevent an American from unlawfully killing “Cecil”, the southern African country's best-known lion. The American, Walter James Palmer, a Minnesota dentist who paid $50,000 to kill the lion, has left Zimbabwe. He says he did kill the animal but believed the hunt was legal and that the necessary permits had been issued. (Photo by Eric Miller/Reuters)

In Canada, a small sea lion seems very narcissistic, put on a variety of expressions and gestures to the camera, self-shot was exhilaration, it does not know the photographer Jon Cornforth next to it quietly photographed its body posture.

Baby clouded leopards, born early in March 2015, are presented by zoo keepers at the Olmense Zoo in Olmen, Belgium, April 16, 2015. The clouded leopard is an endangered species with only some 10,000 specimen remaining on earth, said Robby Van der Velden, a biologist at the Olmense Zoo. (Photo by Yves Herman/Reuters)