The Elephant Seal: Linking Phenotypic Variation with Behavior and Fitness in a Sexually Dimorphic Phocid

Abstract

Southern (Mirounga leonina) and northern elephant seals (M. angustirostris) are extreme in nearly all aspects of their behavior, from fasting to fighting to diving to navigation. Behavioral research over the past six decades has provided unparalleled insight into key elephant seal traits that drive survival and reproductive success. Specifically, the extensive study of northern and southern elephant seals using innovative methodologies and technologies has shown how behavior during reproduction, molt, and foraging interact to drive the evolution of body mass. Their extreme sexual dimorphism has led to pronounced niche segregation across three-dimensional space, allowing a synthetic assessment of physiological constraints in an ecological context. Additionally, their behavioral feats have made elephant seals successful remote sensing platforms for measuring the physical and biological characteristics of the open ocean. Promising directions for future research include interactions between intrinsic and extrinsic factors and their relationship to individual quality, especially for juveniles and adult males.