I love the strong emotions in this picture. Typically the lioness is the one in charge, the one who hunts and takes care of the babies but here she surrenders, gives up her power momentarily to engage to the lion's sweet play.
The wild Gaur (Bos gaurus), also called Indian bison, is the largest extant bovine, native to South Asia and Southeast Asia. It weighs between 3000 to 4000 pounds. The species is listed as vulnerable on the IUCN Red List.