An elephant bull charges a female hippopotamus as her calf scampers to safety, in Erindi Private Game Reserve in Windhoek, Namibia. (Photo by Rian van Schalkwyk/Barcroft Media)

Boeing B-29 (#10) from the 24th Bomb Squadron, 6th Bomb Group after an emergency landing at Iwo Jima on April 24,1945. (Photo by U.S. Air Force)

Brazilian Tapir Tique is treated to a nice cold shower by the zoo keeper at Taronga Zoo on January 8, 2013 in Sydney, Australia. Temperatures are expected to reach as high as 43 degrees around Sydney today. (Photo by Marianna Massey)

A glamour model Lacey Banghard attends a photocall for PETA to encourage pet owners to have their cats and dogs sterilised at Picadilly Circus on January 22, 2013 in London, England. (Photo by Ben Pruchnie)

A menacing swarm of locusts that entered southern Israel earlier this week has been largely smitten, according to the Israeli government and local reports. But some of the insects' ilk may be back later this week. (Photo by Eliyahu Hershkovitz)

A giant river otter, the world's largest otter species, looks out of its enclosure at the newly completed River Safari in Singapore, on March 25, 2013. (Photo by Wong Maye-E/Associated Press)

People at a Czech Stop look at a cloud of smoke rising from the explosion in West, Texas, April 17, 2013. (Photo by Andy Bartee via Dallas Morning News/MCT)

Maria, 18, wearing a traditional Sevillana outfit, poses for a portrait during the traditional Feria de Abril (April fair) in the Andalusian capital of Seville April 16, 2013. (Photo by Marcelo del Pozo/Reuters)