A man walks with a camel at Birqash camel market on January 27, 2012 in Cairo, Egypt. On the edge of the western dessert, thousands of camels are bought and sold every Friday at Brqash camel market, one of the biggest in the Middle East. (Photo by Jeff J. Mitchell/Getty Images)

Gentoo penguins begin the breeding season at Edinburgh Zoo on March 1, 2011 in Edinburgh, Scotland. The zoo keepers have just installed the nest rings in the penguin enclosure. The male penguins will then collect pebbles and offer them to the females to fill nest rings with, this helps keep the eggs and chick up off the ground and is part of their courtship display. (Photo by Jeff J Mitchell/Getty Images)ю EDINBURGH, SCOTLAND – MARCH 01

Vintage car enthusiast Peter Bett, attends a auction at Strathmore Vintage Vehicle Club on April 2, 2011 in Glamis, Scotland. Buyers from around the UK and Europe are attending the auction of cars collected by William Cunnigham. Among the many rare classics on sale is a 1939 McEvoy Steyr, thought to be the only one in existence along with a Hotchkiss Grand Sport Roadster from 1936. (Photo by Jeff J Mitchell/Getty Images)

Demonstrators march on a Slutwalk on June 4, 2011 in Glasgow, Scotland. Glasgow's first ever sl*t walk made its way through the town center streets in a bid to raise awareness about commonly-held attitudes towards rape and sexual assault. (Photo by Jeff J Mitchell/Getty Images)

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)

A Maasai man in ceremonial dress poses for visitors to take photographs of him in front of one of around a dozen pyres of ivory, in Nairobi National Park, Kenya Thursday, April 28, 2016. The Kenya Wildlife Service (KWS) has stacked 105 tons of ivory consisting of 16,000 tusks, and 1 ton of rhino horn, from stockpiles around the country, in preparation for it to be torched on Saturday to encourage global efforts to help stop the poaching of elephants and rhinos. (Photo by Ben Curtis/AP Photo)

In this photo taken Wednesday, March 8, 2017, a woman herder sits with her goats in a remote desert area near Bandar Beyla in Somalia's semiautonomous northeastern state of Puntland. Somalia has declared the drought a national disaster, part of what the United Nations calls the largest humanitarian crisis since the world body was founded in 1945, and with animals being central to many the drought threatens their main sources of nutrition and survival. (Photo by Ben Curtis/AP Photo)