A whaler is a type of sailing ship that was used for hunting and capturing whales. These ships were equipped with specialized equipment such as harpoons, lances, and try-pots to process the captured whales. Whaling has been practiced by various cultures throughout history, but it became most prominent during the 19th century when large commercial fleets hunted whales for their oil, which was used in a variety of industrial applications such as lighting and machinery lubrication. The practice of whaling declined significantly after World War II due to changes in technology and shifting cultural attitudes towards animal welfare. Today, the term "whaler" is often used metaphorically to refer to someone who engages in a particular activity with great enthusiasm or dedication, regardless of whether that activity involves hunting whales or something else entirely.