The efficiency with which mothers convert acquired energy into milk is a key determinant of the magnitude of parental investment in mammals; however, the mech~isms underlying lactation efficiency are poorly understood. Investigations on northern eleph . . .

Our aim was to examine the foraging behavior of northern elephant seals Mirounga angustirostris during the 1997–98 El Niño and compare it to foraging in others years. Given their deep diving and spatial distribution, their immediate response to a seve . . .

Data-recording tags applied to marine animals store data for later retrieval and can return valuable information on animal behavior and ecology, including habitat preference, physiology, and movement patterns, as well as environmental data. If properl . . .

Marine mammals are a conspicuous faunal element of the Southern Ocean ecosystem and have evolved specialized life history patterns to live there. Six species of pinnipeds inhabit the Southern Ocean, including five species of true seals (family Phocida . . .

Background: The condition of many marine mammals varies with fluctuations in productivity and food supply in the ocean basin where they forage. Prey is impacted by physical environmental variables such as cyclic warming trends. The weaning weight of n . . .

Long-term fasting is a component of northern elephant seal (Mirounga angustirostris) life history requiring physiological adaptations to nitrogen conservation. Plasma free amino acids (FAAs) were determined for five elephant seal pups during the secon . . .

The miniaturization of electronic components and sensors has improved technology for ocean and atmospheric sampling as well as in other related fields. Small, electronic tags, for example, have enabled research on the behavior and movements of oceanic . . .

We test the hypothesis that the New Zealand sea lion is physiologically better equipped for prolonged, continuous diving than other otariids (fur seals and sea lions) by measuring its blood volume, an important component of its oxygen storage. Mass, h . . .

We asked if non-gestating adult female southern elephant seals, Mirounga leonina, from Peninsula Valdes, Argentina, forage on the wide continental shelf off the peninsula during the post-breeding trip to sea (PB females), or whether they forage in dee . . .