This family of warthogs regularly visited our campsite in the Ethiopian highlands so I set up a remote camera with a wide-angle lens to photograph them as they rummaged around for food. They just had a mud bath. (Photo by Will Burrard-Lucas/Caters News Agency)

Dr. Lisa Ballance (NOAA Fisheries Service) with a curious calf – this is a Type C killer whale, a fish-eater.

A female black lemur (Eulemur macaco), looks at a camera in its enclosure at Bioparc Fuengirola in Fuengirola, near Malaga, southern Spain, February 8, 2017. (Photo by Jon Nazca/Reuters)

A soldier from the South Korean army special forces breaks stone plates with her head during a martial arts demonstration for Memorial Day at Korea War Memorial Museum in Seoul, South Korea, Monday, June 6, 2016.(Photo by Ahn Young-joon/AP Photo)

A new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

It’s a tradition that dates back hundreds of years, where two stallions fight over a female to ring the Chinese new year. And when it’s the Year of the Horse, the fights are considered to be even more significant. They’re held in small villages across southern China and have been condemned by animal rights groups, including Hong-Kong based Animals Asia. But those who participate in the events defend the fights and insist they take care of the animals.

Burmese monks take their yearly exam December 13, 2011 in Bago, Myanmar. Around 1,400 monks from Bago province took part . (Photo by Paula Bronstein /Getty Images)