Geoscience Reference
In-Depth Information
A humpback whale lunge feeds through a shoal of herring and krill.
It is no coincidence that all five species of great whales common to the gulf—the humpback, fin, minke, sei,
and right whales—are baleen whales, adapted to feeding on the gulf 's cornucopia of plankton. There are two
general groups of cetaceans, an order of mammals that includes whales, porpoises, and dolphins: the odonto-
cetes, or toothed whales, and the mysticetes, or baleen whales. “Mysticetes” derives from the Greek word for
mustache, mystax, and refers to the hairy appearance of the whale bone, or baleen, that hangs from the whale's
upper jaws. The baleen consists of a series of overlapping horny plates that are fringed on the inner margin
with hairlike bristles. These bristles act as a sieve to strain food—zooplankton, shrimp, or small fish—from the
water.
With the exception of the right whale, the whales in the gulf are all ror-quals, a term derived from the Nor-
wegian ror, tube, and hval, whale. Ror refers to the grooves or folds on the throat and chest. When the whale
gulps water while feeding, these grooves expand enormously, like a giant accordion or bellows, and the whale
then forces water out through the baleen by raising its tongue, retaining the food items in the baleen for swal-
lowing. The right whale, however, has no throat grooves and is a more passive feeder, continuously straining
out the food organism while swimming through swarms of small copepods or krill.
These whales are found in different parts of the gulf at different times of the year, depending on where the
heaviest concentrations of food are. Today, the most endangered great whale on the planet is the North Atlantic
