True, phocid seals have the shortest known lactations relative to body mass, during which mass transfer of adipose stores from mother to offspring occurs at an unrivalled rate and extent. The mothers of most species of seal fast until weaning whilst their pups gorge on the most fat-rich milks known. This results in a dramatic reduction in maternal blubber mass while pups may triple their body weights before weaning. Mothers mo...

Mothers of the Atlantic grey seal, Halichoerus grypus , lactate for about 20 days, during which they do not feed and may have no access to water. Following weaning, they depart to sea leaving their pups unattended and unfed for up to another 40 days. We are interested in how this lactation strategy supports the pups’ rapid growth and development while also preparing them for their long fast before independently going to sea. W...

Grey seals ( Halichoerus grypus ) are a qualifying feature of three special areas of conservation (SACs) in Wales, yet relatively little is known of their site use along this coastline. Since 1992, many individuals and organisations have contributed to a grey seal photographic identification database held by Natural Resources Wales, which is one of the largest and oldest of its kind, providing key information from grey seal ha...

Balancing time allocation among competing behaviours is an essential part of energy management for all animals. However, trade-offs in time allocation may vary according to the sex of the individual, their age, and even underlying physiology. During reproduction, higher energetic demands and constrained internal resources place greater demand on optimizing these trade-offs insofar that small adjustments in time-activity may le...

There has been extensive recent interest in the concepts of behavioral types, behavioral syndromes, and personalities in nonhuman animal species. Evidence for behavioral types now exists from a wide range of taxa, from mollusks to mammals. However, marine mammals are poorly represented in this literature. Here, we describe an in‐field experimental test of behavioral types in breeding gray seals, using a remotely controlled veh...

Microsatellites were used to investigate fine‐scale spatial and temporal genetic structure of a gray seal breeding colony, using samples collected throughout the colony (1997) and more extensive local sampling (2000–2002). Previous behavior of breeding seals on North Rona, including philopatry and high breeding site fidelity, suggested female kin may cluster together. However, low F ST scores indicated no genetic differentiati...