The Minke whale is a species complex of baleen whales, belonging to the suborder Mysticeti, characterized by having plates of baleen instead of teeth for filter feeding. These whales are the smallest members of the rorqual family, Balaenopteridae, which also includes the Blue and Fin whales. Minke whales are widely considered one of the most abundant rorqual species globally, maintaining a relatively stable population status across much of their range. Their importance in the marine food web is significant as a numerous predator species.
Defining Physical Characteristics
The Minke whale exhibits a sleek, streamlined body shape typical of the rorqual family, designed for fast swimming. Adult Common Minke whales typically reach lengths of about 8.5 to 10 meters (28 to 33 feet) and can weigh up to 10 metric tons, with females generally being slightly larger than males. Their coloration is generally counter-shaded, featuring a dark gray, black, or brownish dorsal side and a bright white underside.
A highly distinctive feature for identification, particularly in the Northern Hemisphere, is a prominent white band located across the middle of each dark flipper. Like all baleen whales, the Minke possesses 50 to 70 ventral grooves, or pleats, that run from the throat to the chest, allowing the mouth to expand dramatically when engulfing water and prey.
Inside the mouth, Minke whales have between 230 and 360 short, yellowish-white baleen plates lining each side of the upper jaw. These keratinous plates are fringed into fine bristles, which serve to filter small organisms from the large volumes of water taken in during feeding. The head is characterized by a narrow, pointed rostrum, which gives the whale a sharp profile.
Distribution, Diet, and Migration
Minke whales are found throughout the world’s oceans, from the edges of polar ice to tropical and subtropical waters. This widespread presence reflects their adaptability to various marine environments and prey availability. They are often found in both coastal, inshore waters and oceanic, offshore areas, sometimes venturing further into polar ice domains than other baleen species.
The species undergoes extensive seasonal migration between different latitudes. Minke whales typically spend the summer months feeding in the highly productive, cooler waters of the high latitudes, such as the Arctic and Antarctic. As winter approaches, they migrate toward warmer, low-latitude waters closer to the equator, where mating and calving occur, and feeding activity is reduced.
Minke whales are considered generalist feeders, opportunistically adapting their diet based on the most abundant local prey. Their diet primarily consists of small schooling fish, such as capelin, herring, cod, and sand eels, as well as various crustaceans, particularly krill. They use a lunge-feeding technique, rapidly swimming into schools of prey with an open mouth to engulf a large volume of water and organisms.
Recognized Species and Subgroups
The term “Minke Whale” refers to two distinct species: the Common Minke Whale (Balaenoptera acutorostrata) and the Antarctic Minke Whale (Balaenoptera bonaerensis). The Common Minke Whale is distributed across the Northern Hemisphere, while the Antarctic Minke Whale is confined to the Southern Hemisphere. The two species diverged approximately 4.7 million years ago.
A primary morphological distinction involves flipper coloration. The Common Minke Whale generally features the diagnostic white band on its flippers. The larger Antarctic Minke Whale usually lacks this distinct band, having flippers that are typically solid gray. Antarctic Minke whales can also be slightly larger, reaching up to 10.7 meters (35 feet).
Within the Common Minke Whale species, taxonomists recognize several subgroups, including the North Atlantic and North Pacific populations. A third form, known as the Dwarf Minke Whale, is found in the Southern Hemisphere. Dwarf Minke whales are smaller and have a white flipper patch, distinguishing them from the larger Antarctic Minke Whale with which they share Southern Ocean waters.