The extreme polygamy of elephant seals leads to premature death of young males. In this respect informs Guard.
Elephant seals vary considerably in size, with adult males being five times heavier than adult females. Differences in size usually begin to show when animals mature, between the ages of three and six. At the same time, animals are distinguished by pronounced polygamy – one large male beats other males and mates with dozens of females, the number of which can be up to a hundred. Such men are called “masters of the coast”, they are no more than 4% of the population. To gain an advantage, elephant seals must be large and fat.
Now Sophia Woltzke and her colleagues have discovered that this type of behavior leads to taking huge risks while hunting. Study on 14,000 elephant seals (mirounga leonina), showed that, on Macquarie Island in the Southwest Pacific, male and female survival rates were roughly comparable at young age, while male survival rates dropped sharply after reaching eight years of age, falling to 50%, while female survival rate remained at 80%. . The researchers believe that competitive pressure on maturing males causes them to gain weight as quickly as possible, resulting in lower survival rates when foraging at sea in areas where males are at high risk of predation.
“To be able to fight off other males and survive on land for weeks or months without food, they need to store up their fat reserves,” the scientists say.
Although male elephant seals become biologically fertile at about six years of age, they are rarely competitive enough to breed before age 9-12.