1977, Bougneres et al. 1986).

Limited published data suggest that the neonatal Weddell seal may have a particularly large brain ABT888 relative to adult brain mass (Sacher and Staffeldt 1974, Elsner and Gooden 1983). Neurophysiological studies on visually evoked potentials (Gruenau et al. 1975) indicate that the brain of the newborn Weddell seal is also developmentally advanced. As a large brain in pups implies greater brain substrate demands, both relative to body stores and relative to the metabolic capacity for meeting these demands (Elsner et al. 1969, Elsner and Gooden 1983), the brain is expected to exert a particularly strong influence on nutrient and energy requirements in the suckling period, with potential effects on maternal lactation strategies (Eisert et al. 2013). We undertook a study of brain mass and cranial capacity in the Weddell seal to determine if this species

does in fact have a particularly large, well-developed brain at birth. As source material, we took advantage of the considerable mortality of newborn Weddell seals in breeding colonies, including stillbirths, accidental mortality, and abandoned pups (Schreer et al. 1996, Hastings and Testa 1998). Adult females also die during the lactation period (Stirling and Greenwood 1972, Kaufmann et al. 1975), possibly as a result of the metabolic stress of lactation, but causes of mortality

have not been well studied. We supplemented this material with specimens obtained from annual culls of Weddell seals carried out in the 1960s (Stirling 1968). Due to the limited published data on brain ontogeny in pinnipeds, we also compared our results to published data in cetaceans and terrestrial taxa to assess whether brain ontogeny in the Weddell seal is exceptional relative to other mammals. Carcasses of Weddell seals (2 adult females and 10 neonatal pups) were recovered in the vicinity of Hutton Cliffs and nearby Turtle Rock (77°44′S, CYTH4 166°30′E), on the eastern side of McMurdo Sound, Antarctica, from October to December 2007. Of the carcasses we recovered (Table 1), four pups were observed dead shortly after birth and believed to be stillborn, one of which was considered premature based on its small size (7547; Table 1); two (7524, 7639) had been abandoned prior to death and had very little observable body fat (blubber depth measured on the mid-ventrum, 0.2 cm or less; Table 1); one (7671) had a distorted face and dislocated jaw (determined by radiography), indicating trauma likely due to crushing by an adult.