The Minke whale is a member of the rorqual family, a group of baleen whales distinguished by their pleated throat grooves and streamlined bodies. This species is the smallest of all rorquals and is one of the most frequently sighted baleen whales across the globe, inhabiting waters from the tropics to the polar ice edges. Its scientific name, Balaenoptera acutorostrata, translates to “winged whale, sharp snout.” Understanding its size, coloration, and head anatomy helps in identification.
General Dimensions and Streamlined Form
The Minke whale possesses a slender, sleek body shape that allows it to be an exceptionally fast swimmer, capable of reaching speeds exceeding 20 kilometers per hour. Adult Minke whales typically reach a length between 7 and 10.7 meters, with females generally growing slightly longer than males. This size range establishes it as the smallest of the “great whales.”
An adult Minke whale generally weighs between 5 and 10 metric tons, or 10,000 to 20,000 pounds. Its body tapers smoothly from the head to the tail, contributing to its hydrodynamic efficiency. The dorsal fin is tall, sickle-shaped, and positioned approximately two-thirds of the way down the back, a location that helps observers distinguish it from other cetaceans.
Key Identifying Markings and Coloration
The Minke whale exhibits a coloration pattern known as countershading, which provides camouflage in the ocean environment. Its back and upper sides are typically dark grey, black, or brownish, contrasting sharply with its bright white belly and underside. Some individuals also display a pale chevron-shaped marking located on the back just behind the head.
The most distinctive feature for identifying the common Minke whale is a prominent, bright white band that crosses the upper surface of each pectoral flipper. This highly visible marking is present on Northern Hemisphere Minke whales and helps differentiate the species from other dark-colored rorquals. The curved and relatively tall dorsal fin often displays unique nicks or scars used for photo-identification of individual animals.
Unique Head and Baleen Structure
The head of the Minke whale is narrow and pointed, reflected in the species’ scientific designation, acutorostrata, or “sharp snout.” A single, prominent ridge runs down the center of the rostrum, or upper jaw, from the tip to the blowholes. This feature is a consistent anatomical detail that helps differentiate the Minke whale from other rorquals, which may have multiple ridges on their heads.
The feeding apparatus of the Minke whale consists of baleen plates, fibrous structures made of keratin that hang from the upper jaw instead of teeth. It possesses approximately 230 to 360 short, cream-colored or yellowish-white baleen plates on each side of its mouth. Like all rorquals, the Minke whale has a series of longitudinal folds, known as ventral pleats or grooves, that run from its throat to its belly, totaling between 50 and 70 pleats. These grooves allow the throat to expand significantly, enabling the whale to engulf large volumes of water and prey, such as krill and small schooling fish, during lunge feeding.