Long, Slender Bodies Differentiate Sei Whales From Bulkier Rorquals

Adult sei whales can reach lengths of 18 to 20 meters while maintaining a relatively narrow profile.

This morphology reduces drag and allows rapid directional changes during feeding or predator avoidance.

Subtle differences in body proportions assist marine biologists in distinguishing sei whales from fin and Bryde's whales at sea.