ne committed photographer spent a grand total of 3,000 dive hours trying to get the perfect shots, capturing beautiful images of a rare shark feeding frenzy. Laurent Ballesta’s images show the glimmering gray reef sharks hunting in swift packs, flying through the water and feasting on the likes of helpless grouper. (Photo by Laurent Ballesta/Caters News Agency)

A Kamchatka Brown Bear cub eats frozen fruits during a Christmas feeding session at Hagenbecks zoo in Hamburg, northern Germany on December 5, 2014. (Photo by Fabian Bimmer/Reuters)

A diver dressed in a Santa Claus costume performs with sardines at the Coex Aquarium in Seoul, South Korea, Wednesday, December 9, 2015. (Photo by Ahn Young-joon/AP Photo)

In this May 12, 2017 photo, Pupy, an African elephant, stands in the doorway of his enclosure at the former city zoo now known as Eco Parque in Buenos Aires, Argentina. A year ago the 140-year old Buenos Aires zoo closed its doors and was transformed into a park. The first director decided that the animals should be housed in buildings that reflected their countries of origin. A replica of a Hindu temple was built for the Asian elephants. (Photo by Natacha Pisarenko/AP Photo)

To most of us, hand-feeding crocodiles might sound like a one-way ticket to a watery grave. But for Jose Eduardo Chaves Salas, 32, coming within inches of the fearsome creatures’ razor-sharp teeth is all in a day’s work. He runs Jose's Crocodile River Tour on the Tarcoles River in Costa Rica, where tourists can watch him feed crocs up to 17 feet long. Photo: A tour guide shows a thumbs up as he sits on top of a crocodile on the Tarcoles river in Tarcoles, Costa Rica. (Photo and caption by Barcroft Media)

Jo-Anne McArthur’s book of photographs puts the spotlight on ethics of zoos around the world. Accompanied by essays by Born Free Foundation’s Virginia McKenna and philosopher Lori Gruen, the images and stories are also shared online through “A Year of Captivity”. Here: Asian Elephant, Denmark, 2016. (Photo by Jo-Anne McArthur/Born Free Foundation/The Guardian)

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)