John Cancalosi / Male Spanish ibex {Capra pyrenaica} courting female ibex on mountain side. Spain.

Tim Laman / Tule elk (Cervus elaphus nannodes) stag roaring / rutting, an endemic subspecies to California. Point Reyes National Seashore, California.

Edwin Giesbers / Silhouette of Red Deer (Cervus elaphus) stag calling during rut, Dyrehaven, Denmark

Richard Du Toit / Steenbok {Raphicerus campestris} male testing urine of female during courtship, Kruger NP, South Africa

Richard Du Toit / Warthog {Phacochoerus aethiopicus} pair mating, Chobe NP, Botswana