Veteran naturalist and photographer Raghu Kulkarni (@naturalist_raghukulkarni) thought he had already captured the wildlife moment of a lifetime when a black leopard crossed a road in India's Manas National Park. Then he lowered his camera, and two melanistic cubs stepped out behind her. What happened? Kulkarni shared footage of what he described as an exceptionally rare encounter. View this post on Instagram A post shared by Raghunandan Kulkarn…