Jocelyn Brown-Saracino

Effects of unique topographical features on Grey Seal (Halichoerus grypus) breeding behavior

The goal of Jocelyn's project is to investigate the ways in which habitat influences the behavior of grey seals (Halichoerus grypus).  Her research is being conducted on Muskeget Island, a small island in Nantucket Sound.  During December and January, a growing colony of grey seals utilize the island to pup and breed.  Jocelyn plans to investigate:   1. how a large saltwater pond on the island affects the breeding behavior of males both in and near the pond and 2. whether adult male and female grey seals are using the pond to aid in thermoregulation.  She hypothesizes that a set of males will inhabit the pond for extended periods of time during the breeding season and will exhibit a similar set of behaviors.  These behaviors will comprise an alternative mating strategy that results in a degree of reproductive success.  She also predicts that there will be a high male to female ratio on the beach adjacent to the pond because males will have access to females on the beach from both the ocean and the pond.  This may result in high rates of female harassment and male-to-male aggression.  Finally, she hypothesizes that more seals will utilize the pond on warm, sunny, and calm days compared to cool, overcast, and windy days, suggesting that the seals are using the pond to aid in thermoregulation.  Collectively, these questions will broaden our understanding of the plasticity of breeding behavior in respect to topographical features, provide insight into shallow water aquatic mating strategies in grey seals, and provide information on thermal tolerance of grey seals during the breeding season.

For more information about the project, please email Jocelyn at