Margarine, that spreadable, butter-like substance, was until the 1940s or so made with whale oil.
In fact, whale oil and margarine were so important to the World War II economy that Britain declared it a commodity essential for national defense.
Consumers today would be horrified if margarine contained whale, which is largely thought to be off-limits to hunting these days. Today, margarines are made with vegetable oils.
In fact, popular outrage over whale hunting helped end the practice. It was time, after all. Technology has replaced whales as a source of fuel and fat.
Iceland, Norway and Japan still have whaling industries, although the practice is illegal nearly everywhere else.
During the 1700s and 1800s, whales were relentlessly hunted for their oil. Whale oil, particularly the so-called spermaceti from sperm whales, was used for heating, soaps, and lubricants as well as during the processing of rope and textiles. Demand was highest for its use as lamp fuel because it produced a smokeless flame. It was such an improvement in light quality and consistency that it created the standard for light production that we still use today: the lumen. Fortunately for the whales, kerosene was invented in 1849. Kerosene could be stored for long periods, and it burns without a fishy odor.
Margarine saved the whale industry in 1869 when it was used as a cheaper substitute for butter. German per capita consumption was 17.5 pounds per year in 1930, and led to the merger of Lever
Brothers and Margarine Unie to create the Unilever company, once the world’s largest purchaser of whale oil, according to Atlas Obscura.
Whale-based products are prohibited today in most of the world.