Big boys get big girls: Factors influencing pupping site and territory location in Australian fur seals

Abstract

AbstractTo examine the factors influencing birth site selection and territory location in Australian fur seals (Arctocephalus pusillus doriferus), habitat variables (slope, substrate, and elevation) were quantified in seven zones within a breeding colony on Kanowna Island (39º15′S, 146º18′E), southeastern Australia. Distribution across the colony was not uniform with zones at low elevations (i.e., close to water) being preferred areas, having earlier occupancies and greater female densities. Body length of females and territorial adult males was assessed using laser‐metrics. Average female length increased throughout the breeding season, within zones and across the colony, with larger females arriving to give birth later. Larger females also occupied areas of lower elevation close to water. Adult male body length had no influence on territory size, but was positively correlated with the number of females in harems (r2 = 0.70, P < 0.05) and female length (r2 = 0.87, P < 0.01) within harems. By monopolizing larger females, adult males may enhance their reproductive success as these individuals are more likely to give birth and have greater weaning success.