Whales Cetaceans

Whales (order Cetacea) are mammals that returned to the sea approximately 50 million years ago from wolf-like land ancestors (Pakicetus). The blue whale (up to 33m, 173 tonnes) is the largest animal ever to have lived on Earth — larger than any dinosaur. Humpback whales produce complex songs (up to 30 minutes, changing over time, transmitted through populations) that are the most elaborate sound sequences of any non-human animal. Whaling devastated whale populations — commercial whaling (19th-20th centuries) reduced blue whale populations from 200,000-300,000 to approximately 1,000-3,000 by the 1960s. The International Whaling Commission's commercial whaling moratorium (1986) has allowed partial recovery — humpback whales have recovered strongly; blue whales more slowly. Sperm whales (can dive 2,000m and hold breath for 90 minutes) were the basis of the 19th-century whaling industry (sperm oil as the finest lubricant).