Since 1980, a team of scientists from a consortium of research centers have surveyed the northern right whale population to determine how the whales use their habitats and whether other critical areas exist. To track the whales, researchers had to first learn how to identify and recognize individuals. Such information helps scientists determine whether individual whales return to the same areas every year, which females have given birth, how whales are related to each other, and which ones may have died. Fortunately, right whales are easy to tell apart. All whales have unique patterns of thickened skin patches, called callosities, on their heads.
Many whales also have distinctive scars from encounters with boats.
Since 1980, researchers have traveled out to some of the major habitats to photograph the whales. Then they compare the pictures to a comprehensive catalog of right whale photographs housed at the New England Aquarium. The catalog contains photos dating back to 1935, but most of the records were gathered since 1979. Few previously unidentified adult whales have been photographed in recent years, leading researchers to conclude that they have records of most of the whales in the population. Scientists also have collected tissue samples from the whales to determine both the gender and the lineage of individuals.