Although commercial hunting of sperm whales began in the 18th century, the majority of reported kills took place between 1950 and 1980 when harpoon guns became more widely used. Whaling records show that more than 638,000 sperm whales were killed during this period. Today, population estimates for sperm whales fall in the range of 300,000 to 400,000, significantly down from more than a million whales worldwide before large-scale hunting began in the last century. Sperm whales are currently classified on the IUCN’s Red List as Vulnerable.