The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

People perform Chinese Lion dance in Chinatown during the Chinese Lunar New Year in Lima, Peru on February 5, 2019. (Photo by Guadalupe Pardo/Reuters)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

An Indonesian jockey rides two bulls with a cart during a traditional sport bull race locally called “pacu jawi” in Pariangan of Tanah Datar regency in West Sumatra on December 1, 2018. (Photo by Adek Berry/AFP Photo)

A woman wearing a four-leaf clover-like hairpin takes a selfie nearby Nanluoguxiang street in Beijing, China, September 16, 2015. Wearing antenna styled hairpins in the shape of various flowers and plants at scenic spots has become a new trend in Beijing. (Photo by Kim Kyung-Hoon/Reuters)

A newborn grey seal pup is tended by its mother at Donna Nook, a nature reserve on the county’s coastline managed by Lincolnshire Wildlife Trust in Lincolnshire, UK on November 23, 2015. (Photo by David Tipling/Rex Shutterstock)

A woman takes selfie as municipal workers use cranes to lift carcass of Bryde whale at the Juhu beach, in Mumbai, India, Friday, January 29, 2016. Marine biologists in India were conducting an autopsy on the carcass of 35-foot long Bryde whale that washed ashore on a popular beach in the western city of Mumbai. The beached mammal which appeared to have died at sea two or three days ago was spotted on the beach Thursday by late evening walkers, who informed police. (Photo by Rajanish Kakade/AP Photo)

Siberian Huskies pull a contestant during the “Kara-Dag 2016” open amateur dog sled and skijoring race near the village of Yelovoye in Taiga district, outside Krasnoyarsk, Siberia, Russia, February 21, 2016. Dogs and their owners from various regions of Siberia took part in an annual race. (Photo by Ilya Naymushin/Reuters)