Scott Kraus/New England Aquarium
Surface active groups
Surface active groups (SAGs) are characterized by two or more whales socializing at the surface. Frequent body contact is observed, often with whales rolling on their sides or backs. They generally involve a single female that vocalizes to attract males. The female typically spends most of the time on her back with her genitals out of the water while males clasp her from either side with their flippers. Penises are often observed and SAGs are believed to play a role in mating. However, many SAGs do not lead directly to calving because: 1) SAGs have been seen during almost all months, whereas calving occurs primarily from December through March; 2) some SAGs comprise only males and/or juveniles; and 3) many of the focal females are already pregnant.