A humpback whale breaches off South Africa's Kwa-Zulu Natal South Coast, in this file photo taken July 9, 2004. A study unveiled on Monday showed that the extinction or precipitous population declines of large land and sea mammals has deprived ecosystems of a vital source of fertilization in their dung, urine and, after death, decomposing bodies. (Photo by Mike Hutchings/Reuters)
