Wakodahatchee wetlands, Delray Beach, Florida, US. Equipped with sinewy necks and spear-like bills, great blue herons can lunge with fearsome speed to strike their aquatic prey. Adults will also employ rapid stabbing motions as one aspect of their complex courtship displays; they’re seemingly dangerous moves, but fitting to the intensity of mating season. (Photo by Melissa Rowell/Audubon Photography Awards)

Members of the media film as a ranger performs a post mortem on the carcass of a rhino after it was killed for its horn by poachers at the Kruger national park in Mpumalanga province August 27, 2014. Rhino poachers in South Africa now risk giving themselves away when they shoot thanks to a high-tech, gunfire-detection system being piloted in the country's flagship Kruger National Park. The stakes are high, for rhinos are being slain in escalating numbers for their prized horns, alarming both conservationists and the government since wildlife in South Africa is an important tourist draw. (Photo by Siphiwe Sibeko/Reuters)

A robot is seen on Mount Etna, Italy on July 4, 2017. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany's space programme. (Photo by Antonio Parrinello/Reuters)

Base jumpers leap from the 300-metre high skydeck of Malaysia's landmark Kuala Lumpur Tower against the backdrop of the city's skyline on October 3, 2016 during the annual International KL Tower Base-Jump event. (Photo by Manan Vatsyayana/AFP Photo)

An Afghan refugee family stands by trucks loaded with their belongings as they wait to go back to Afghanistan with others, at the United Nations High Commissioner for Refugees (UNHCR) office on the outskirts of Peshawar February 13, 2015. Afghan immigrants ordered out of Pakistan in what officials say is a bid to root out militants are, some analysts say, scapegoats being used to distract attention from the authorities' failure to end violence. (Photo by Fayaz Aziz/Reuters)

A mechanic assembles a BMW C evolution electric maxi-scooter at the BMW Berlin motorcycle plant February 23, 2015. The storage capacity of the BMW C evolution's high-voltage 8 kWh battery provides a range of up to 100 kilometres and a maximum speed of 120 km/h. (Photo by Fabrizio Bensch/Reuters)

A man watches as high surf crashes into the wall and spills onto Channel Drive in Montecito, Calif., January 7, 2016. Bacteria levels can increase significantly during and after rainstorms as contaminants in the runoff enter the ocean via storm drains, creeks and rivers. (Photo by Mike Eliason/AP Photo)