Description: Tigers have the additional distinction of being the heaviest cats found in the wild. However, the subspecies differ markedly in size, tending to increase proportionally with latitude, as predicted by Bergmann's Rule. Thus, large male Siberian Tigers (Panthera tigris altaica) can reach a total length of 3.5 m and a weight of 306 kilograms, which is considerably larger than the sizes reached by island-dwelling tigers such as the Sumatran, the smallest living subspecies with a body weight of only 75-140 kg.