Humpback whales were hunted primarily for their oil, which served as fuel for lamps, lubricant for machinery, and later as a key ingredient in margarine, soap, and explosives. Their large bodies yielded significant quantities of blubber, and their predictable migration routes and coastal feeding habits made them relatively easy targets compared to faster, more elusive species. For centuries, these whales were worth enormous sums of money, and entire industries rose and fell around the products extracted from their bodies.
What Whalers Wanted From Humpbacks
The most valuable product was whale oil, rendered from the thick layer of blubber beneath the skin. In the 1700s and 1800s, this oil lit homes, lubricated factory equipment, and was burned in street lamps across Europe and North America. A single humpback could produce thousands of liters of oil, making each kill highly profitable.
In the early 1900s, whale oil found an entirely new market. German scientists developed a hydrogenation process that could solidify liquid oils at room temperature, which meant whale oil could now be turned into margarine and bar soap. A byproduct of this process, glycerine, became a crucial ingredient in manufacturing explosives. This shift extended the commercial life of whaling by decades, keeping demand high even as electric lighting replaced oil lamps. The meat also had value: in Greenland, humpback whale meat and skin have been staple foods for centuries, central to both daily meals and cultural celebrations.
Technology That Made Mass Killing Possible
For most of human history, hunting large whales was dangerous and slow. Small boats would row out to a whale, and a harpooner would throw a hand-held weapon, hoping to hold on long enough for the animal to tire and die. Humpbacks were among the easier large whales to catch this way because they swim relatively slowly and tend to stay near coastlines during breeding and feeding seasons. But the kill rate was still low.
Everything changed in the mid-1800s with two inventions: steam-powered ships and the explosive harpoon gun. Steam ships could chase whales at speed, and the new harpoon guns fired projectiles that detonated inside the whale’s body, killing it far more quickly. These technologies meant whalers could now pursue and capture virtually any whale species, anywhere in the ocean. The kill rate jumped dramatically.
Then, in 1925, the first modern factory ship arrived in Antarctic waters. These enormous vessels could haul entire whale carcasses up a ramp in the stern and process them at sea, far from any shore station. Whalers no longer needed to tow carcasses back to land. They could stay out for weeks, killing and rendering whales around the clock in some of the most whale-rich waters on Earth.
The Scale of the Slaughter
The numbers are staggering. In the Southern Hemisphere alone, more than 57,000 humpback whales were killed during the decade from 1910 to 1919. The Northern Hemisphere added another 7,400 during the same period. At South Georgia, a sub-Antarctic island that became a major whaling hub, nearly 25,000 humpbacks were killed in just 12 years between 1904 and 1916. That single location accounted for a devastating share of the global population in barely more than a decade.
Humpbacks were often the first species targeted when whalers moved into a new region because they were accessible and oil-rich. But that also meant their populations collapsed quickly. By the 1920s, Southern Hemisphere humpback catches had already dropped to about 14,000 for the decade, not because whalers had lost interest, but because there were far fewer whales left to find. Whalers then shifted their focus to blue whales and fin whales, cycling through species as each one became too scarce to hunt profitably.
The International Whaling Commission used a standardized measure called the “blue whale unit” to set quotas. Under this system, one blue whale equaled two and a half humpbacks, reflecting the relative oil yield. This accounting framework treated whales as raw material, measured purely by how much product each body could produce.
Why the Hunting Eventually Stopped
Two forces brought commercial humpback whaling to an end: the whales ran out, and the oil became obsolete. By the late 1800s, petroleum-based products like kerosene had already begun replacing whale oil for lighting and lubrication. The hydrogenation breakthrough gave whale oil a second life in food manufacturing, but by mid-century, cheaper vegetable oils were filling that role too. The economic case for whaling weakened steadily.
Meanwhile, humpback populations had been so thoroughly depleted that catching them was no longer worth the effort. The International Whaling Commission moved to protect humpbacks in stages. Greenland, for example, was limited to just 10 humpbacks per year starting in 1955, a number that was further reduced through the 1980s. Broader international protections followed, and the IWC prohibited commercial humpback whaling entirely. Greenland continues a small subsistence hunt under strict quotas, currently set at 9 whales per year, reflecting the deep cultural significance of whale hunting in Inuit communities.
Where Humpback Populations Stand Now
The recovery has been one of conservation’s notable success stories, though it’s uneven. In 2016, NOAA Fisheries identified 14 distinct humpback whale populations worldwide and determined that nine had recovered enough to no longer need legal protection. That left four populations still classified as endangered: Central America, Western North Pacific, the Arabian Sea, and Cape Verde Islands/Northwest Africa. A fifth population, breeding off mainland Mexico, is listed as threatened.
The populations that have bounced back tend to be in regions where whaling ended earliest and where food sources remain abundant. The populations still struggling are generally smaller groups that were hit hardest or face ongoing threats like ship strikes, fishing gear entanglement, and habitat disruption. Recovery from industrial whaling is measured in generations, and humpbacks, which reproduce slowly and don’t reach maturity until around age five, need decades to rebuild what was lost in just a few years of intensive hunting.