Abstract:
The roles of innate navigational abilities, environmental cues and individual learning in
shaping animal habitat selection and migration strategies are poorly understood. Naïve
juvenile southern elephant seals (Mirounga leonina) depart from their natal islands after
weaning unaccompanied by experienced conspecifics and immediately undertake long
foraging migrations into the Southern Ocean, before survivors return to their natal
islands several months later. We describe 35 foraging migrations undertaken by 21
recently weaned (< 1 yr old) southern elephant seals from Marion Island and compare
these with 161 foraging migrations undertaken by more experienced (71 sub-adults, 15
adult male and 37 adult females) seals. Foraging migrations of underyearlings were
shorter in duration and they remained nearer to Marion Island than older seals. Subadults
and adult female seals displayed similar directional travel, foraging over deep
water south of the Subantarctic Front. However, underyearlings travelled in multiple
directions away from the island, showing little evidence of common directional travel.
Underyearlings tracked over multiple migrations during their first year at-sea displayed
little repeatability in foraging ranges and substantial variation in direction and distance
of travel among tracks. In contrast, older seals displayed consistency in their use of
foraging ranges and high levels of repeatability in direction and distance of travel. The
overall dissimilarity in movement patterns exhibited by the underyearling elephant
seals when compared with more experienced seals suggest that individual foraging
strategies of this species are strongly influenced by individual learning, especially during
the first year of life.
