Victor H. Cahalane, chief of the biology division of the National Park Service, stated in 1947 that "during the past 2,000 years, about 106 species and subspecies of mammals have become extinct in the world. Only 35 of these were lost in the first 1,850 years. Thirty-one died between 1851 and 1900. From 1901 to 1945, forty were wiped out. Thus the rate of extinction appears to be increasing."!