Photo gallery: Joshua Holko’s polar wildlife

"I work harder on my photography today than I ever had," says Joshua Holko of his niche in polar regions wildlife photography. "That's because capturing great images in these extreme environments is all about technique and process. It's a matter of hit or miss, and most often it's a miss. I go out looking for three elements: a great subject, great lighting, and great composition. Those three don't come together all that often, but you have to have all three to make a great image." RELATED: How Holko carved out this icy photography niche