Clines in the Pupping Season of the Harbour Seal, Phoca vitulina

Abstract

A review of literature and personal correspondence on the harbour seal suggests that large regional variations and clines occur in the timing of its pupping season. The pupping season, which generally lasts from [Formula: see text] to 2 months in any one area, extends from late January to October over the range of the species. Along the east coast of Asia, young tend to be born later as one goes northeastward. In North America, they tend to be born later going southeast from Alaska to Washington, earlier south from Washington to Mexico, and later north from New England to Baffin Island. Clines cannot be demonstrated for Europe. No reasons are apparent at this time to explain the regional variations or clines.