It is hard to believe that the porpoise is not a fish, but a mammal. Yet it is just as much a mammal as the cow in the fields. Porpoises, dolphins and whales form the order called “Cetacea” of the group of aquatic mammals.

Actually, dolphins belong to the whale family and porpoises are a variety of dolphins. All these animals may be given the general name of whales, or cetaceans.

There are a great many differences between porpoises and other whales and fish. The baby porpoise is fed on its mother’s milk like

other little mammals. It is not hatched from an egg, but is born alive. Porpoises have no gills and breathe air through their lungs. Internally, porpoises have a skeleton, circulatory system, brain, and vital organs that are quite unlike those of fish.

Another important difference is the existence of blubber. Mammals are warm-blooded animals, and blubber conserves their animal heat in the cold waters.

The common porpoise is about 1.6 meters long. The head is round in front, and the underjaw projects slightly. It has a wide mouth with between 80 and 100 teeth. A porpoise is black or grey in color above, and white below, with black flippers.

The porpoise prefers to live in waters near the coast rather than the open sea. It inhabits the North Atlantic but is quite rare in the Mediterranean. Porpoises live in great herds and seem to delight in following ships. There are some species of porpoises that appear in the South Atlantic and the Pacific Oceans.

Porpoise oil, which is obtained from the soft fat of the head and jaw, is used as a lubricant in the manufacture of watches and other delicate instruments because it doesn’t gum up and can resist very low temperatures.