Whale oil is oil obtained from the blubber of whales. Whale oil was sometimes known as train oil, which comes from the Dutch word traan ("tear" or "drop").
Sperm oil, a special kind of oil obtained from the head cavities of sperm whales, differs chemically from ordinary whale oil: it comprises mostly liquid wax. Its properties and applications differ from those of regular whale oil, and it sold at a higher cost when marketed.
Early industrial societies used whale oil widely in oil lamps and to make soap and margarine. With the commercial development of substitutes such as kerosene and vegetable oils, the use of whale oils declined considerably in the 20th century. With most countries having banned whaling, the sale and use of whale oil as of 2016[update] has practically ceased.
Whale oil was obtained by boiling strips of blubber harvested from whales. This process was called "trying out". The boiling was carried out on land in the case of whales caught close to shore or beached. On longer deep-sea whaling expeditions, the trying-out was carried out on the ship itself so that the waste carcass could be thrown away to make room for the next catch.
Baleen whales were generally the main source of whale oil. The oil of baleen whales is exclusively composed of triglycerides, whereas that of toothed whales contains wax esters. The bowhead whale and right whale were considered the ideal whaling targets. They are slow and docile, and they float when killed. They yield plenty of high-quality oil and whalebone, and as a result, they were hunted nearly to extinction.
Whale oil has low viscosity (lower than olive oil), is clear, and varies in color from a bright honey yellow to a dark brown, according to the condition of the blubber from which it has been extracted and the refinement through which it went. It has a strong fishy odor. When hydrogenated, it turns solid and white and its taste and odor change.