Rearing Environment, Sex and Size Impact on Aggression in Seals, 2016

Individual size, sex and rearing environment impact on aggression in newly weaned seals.

Kelly J. Robinson, Patrick P. Pomeroy, Neil Hazon, Simon Moss & Sean D. Twiss

Marine Mammal Science 2016, DOI: 10.1111/mms.12367  (link)

Keywords: aggression; grey seal; mammal; pinniped; ontogeny; size; sex; rearing environment; colony density


Aggressive behavior is an important part of how animals interact with each other. Aggressiveness enables individuals to defend themselves or to exploit opportunities to obtain resources from others. We investigated which physical and environmental factors affect how aggressive gray seal pups are towards each other once weaned from their mothers on the Isle of May breeding colony in Scotland. We found that pups raised on crowded areas of the colony were more aggressive than pups from areas with few seals, and that physical characteristics (sex and size) also influence how aggressive individuals of this seal species are. Males showed a postive correlation between aggression and size, while female size and aggression showed a non-linear relationship. Further research is needed to determine whether heightened aggressiveness in large or high density reared infants persists into adulthood, whether it is consistent throughout an individual’s lifetime, or if this relationship is present in other age groups or species.