“A harem of 127 females is a prize that has to be earned. Where female Southern Elephant Seals ("Mirounga leonina") provide all the parental care, they will only reproduce in the territory of the biggest males, the biggest fathers for their offspring. Females average 400 to 900 kg, while males weigh up to 4 tons; Southern Elephant Seals show the largest sexual dimorphism among land breeding mammals. When a male challenges the head of a harem he needs to prove his strength at a great cost, resulting in a fascinating and captivating fight between the two giants.”