Global wildlife populations will decline by 67% by 2020 unless urgent action is taken to reduce human impact on species and ecosystems, warns the biennial Living Planet Index report from WWF (World Wide Fund for Nature) and ZSL (Zoological Society of London). From elephants to eels, here are some of the wildlife populations most affected by human activity. Here: The maned wolf is among the large mammals in the Brazilian Cerrado that are threatened by the increasing conversion of grasslands into farmland for grazing and growing crops. (Photo by Ben Cranke/Nature Picture Library/Alamy Stock Photo)

Thomas Thwaites, a 34-year-old researcher from London, has spent the past year creating prosthetics that allow him to roam around on all fours like goat.

A dog trainer works with a previously abandoned dog at a police centre in Saltillo, Mexico March 4, 2016. Stray dogs are adopted by the police from a municipal anti-rabies centre and then trained to help the police patrol the streets, and search for drugs, explosives and weapons. (Photo by Daniel Becerril/Reuters)

Sally Gomez drives to rescue of friend Michele Moore in flooded parking lot at Hyannis, Mass., September 9, 1969, after torrential rains of Hurricane Gerda flooded low areas of Cape Cod. Ann Davis of Osterville stands up in roof opening to lend a hand. Sally and Michele are from Centerville on the Cape. (Photo by Frank C. Curtin/AP Photo)

Leon Samson, 24-year-old showman, grimaces as an automobile is driven across his chest at Perth, Australia on October 9, 1960. Samson said the towel on his chest is to prevent the wheel from tearing his flesh. (Photo by AP Photo)

Samba dancers arrive to perform ahead of the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Sunday, August 14, 2016. (Photo by Jae C. Hong/AP Photo)

“The telectroscope (also referred to as “electroscope”) was the first non-working prototype (i.e. conceptual model) of a television or videophone system. The term was used in the 19th century to describe science-based systems of distant seeing. The name and its concept came into being not long after the telephone was patented in 1876, and its original concept evolved from that of remote facsimile reproductions onto paper, into the live viewing of remote images”. – Wikipedia

Photo: Visitors to London wave to people they can see in New York as they peer through the Telectroscope situated by Tower Bridge on May 23, 2008 in London, England. The device named the Telectroscope provides a live visual link up between London and New York, to another Telectroscope by Brooklyn Bridge. (Photo by Cate Gillon/Getty Images)

“NASA's Mars rover Opportunity just celebrated its ninth anniversary on Mars – a mission that was originally meant to last just 90 days...” – The Atlantic. Photo: NASA's rover Opportunity visits Victoria Crater, viewed from orbit by the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter in october of 2006. Opportunity is a small dot on the crater's lip, at top right. Opportunity first reached the crater's rim on September 27, 2006. (Photo by NASA/JPL-Caltech/University of Arizona via The Atlantic)