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)

Students, dressed in a whole array of fancy dress outfits, were pictured on a wild night out to kick off Freshers' Week in Leeds, England on September 21, 2019. Freshers' Week is a period before the start of an academic year at a university or tertiary institutions. During this period, students participate in a wide range of social activities. (Photo by N B (PRESS) LTD)

People and Nature category winner: Why did the sloth cross the road? by Andrew Whitworth (Osa Conservation and University of Glasgow), taken in Osa Peninsula, Costa Rica. “I was driving out from the Osa Peninsula, located on the southern Pacific coast of Costa Rica on a dark, stormy day. This female three-toed sloth (Bradypus variegatus) had luckily just about made it across the road, and the drivers of the Toyota on this occasion had spotted her in good time”. (Photo by Andrew Whitworth/2019 British Ecological Society Photography Competition)

In this October 15, 2014 file photo, Katsu Nakamura, sky division manager for Yamaha USA, moves the RMax unmanned helicopter into position before a demonstration of its aerial application capabilities at the University of California, Davis' Oakville Station test vineyard in Oakville, Calif. Researchers at UC Davis have been studying the effectiveness of the drone's ability for spraying pest control and nutritional materials on the test vineyard in California's Napa Valley. (Photo by Rich Pedroncelli/AP Photo)

A undated handout image provided by the Bochum University of Applied Sciences (Hochschule Bochum) on 04 October 2013 shows the German team Bochum's Cruiser class solar car during a test drive in the Northern Territoty, Australia, 16 September 2013. The Dutch vehicle is competing in the World Solar Challenge, driving from Darwin to Adelaide starting on 06 October 2013. (Photo by Hochschule Bochum/EPA)

In this Wednesday, December 2, 2015 photo, Dr. Gal Kelmer, head of the department of large animals, unties a horse after its operation at the University's Koret School of Veterinary Medicine in Rishon Lezion, Israel. “Horses have an instinctive response of flight from danger”, Kelmer said. “The minute they wake up they start trying to stand and run, even if they don't have control of their limbs. So then they fall”. (Photo by Oded Balilty/AP Photo)

“Sidney D. Gamble (July 12, 1890 – 1968) was born in Cincinnati, Ohio, to David Berry and Mary Huggins Gamble; grandson of James Gamble, who, with William Procter, founded Procter & Gamble in 1837. in 1912 he graduated magna cum laude from Princeton University with a Bachelor of Literature degree and was elected to Phi Beta Kappa. He visited China for four extended periods, 1908, 1917–1919, 1924–27, and 1931–1932, doing Christian social work for the Y.M.C.A and conducting social surveys. He is now best known for his remarkable and extensive photographs of Peking and North China.” – Wikipedia. (Photo by Sidney David Gamble via Duke University Libraries)

Photo: Hillcoat Riding Fu Tu. China, An Xian, 1917-1919. P.S. All photos are available in high resolution.

“A robot suit that can help the elderly or disabled get around was given its global safety certificate in Japan on February 27, 2013, paving the way for its worldwide roll-out”. Photo: Robot suit “Hybrid Assistive Limb (HAL)” worn by a man developed by University of Tsukuba is seen lifting a 30kg weight during 2005 International Robot Exhibition on November 30, 2005 in Tokyo, Japan. By wearing the power suit, it makes it easier to move and lift heavy things. (Photo by Koichi Kamoshida)