Blue whales are the largest animal ever known to have lived on earth, even larger than any dinosaur. Blue whales average 24 metres in length and can weigh up to 136 tonnes. Females are larger than males. Blue whales have greyish blue skin with white spots and a small dorsal fin set far back on their body. They can move at speeds of up to 48 km/h and dive as deep as 500 metres, lasting 10 to 20 minutes underwater.
Blue whales use baleen plates to strain food, usually krill, from the water. These animals spend winters in temperate and subtropical areas and travel to polar regions for summer. They usually travel alone or in small groups of 2 to 4 whales.
Whaling of blue whales
Unfortunately, due to their large size and therefore high commercial value, blue whales were extensively hunted. The arrival of industrial whaling using faster boats and harpoon guns allowed for increased hunting on blue whales, and by the 1960s the species was nearly extinct.
Despite decades of protection, blue whale populations have yet to recover from the impacts of commercial whaling. It’s estimated that the worldwide population of blue whales is only 1,200 to 3,000, and therefore they are considered an endangered species.
Blue whales now face other threats such as marine and noise pollution, entanglement in fishing gear, collision with ships and climate change.