Blue whales are the largest animals on the planet. They live in every ocean except for the Arctic, and are divided into 5 different subspecies. The whales that live in the Antarctic are huge - getting up to 110 feet and 330,000 pounds, while other blue whales are smaller (but still humongous) getting up to 90 feet and 100,000 pounds. Females are usually bigger than males. A blue whale has hearts the size of a car.
Generally they will live in colder waters during the summer and then swim to warmer waters in the winter. Mostly, Blue whales swim around 5 miles an hour, but if need be can swim more than 20 miles per hour in short increments.
Blue whales spend most of there time alone, but will sometimes swim in groups. Whales emit loud sounds, and it is thought they can be heard from other whales from up to 1,000 miles away. These sounds are used for communication and possibly echolocation.
Blue whales mostly eat tiny animals called krill, occasionally eating small fish and crustations. They are baleen whales, filter feeding by gathering krill in their mouths, than flushing out the water through their baleen plates that keep the krill inside. Blue whales need to eat four tons of krill a day.
Blue whales are pregnant for close to a year, and then will give birth to a calf that alread weighs 3 tons and is 25 feet long. Once born calves will nurse for up to 7 months. Blue whales reach sexual maturity after 5-15 years, and will then have calves every 2-3 years. Blue whales can live to be 80-90 years old.
Image courtesy of Chase Dekker (WWF)
The number of blue whales today is just a fraction of the number it was before wailing for meat and blubber became popular in the early 1900s. However, populations are currently increasing globally! The most devastating issue blue whales face are vessel strikes and entanglement in fishing gear. Vessel strikes are when ships and boats hit a blue whale. This can deeply injure a whale and may even kill the whales all together. This has affected blue whales in all of the regions but especially the ones in regions with higher boat traffic. Blue whales can also easily become entangled in fishing gear such as traps, pots and nets. They can become stuck on the seafloor or drag the gear for long distances which can lead to exhaustion, compromised feeding ability, severe injury, and sometimes death.
Blue Whales are a very important part of the ecosystem of the ocean. They eat very large amounts of krill and algae which are very important to keep the ecosystem running. The remains of passed whales also feed hundreds of aquatic animals. They are so big that some of their remains can fall very deep in the ocean. This feeds the twilight and midnight zones of the oceans when most other food will get eaten before it can reach such depths.
NOAA fisheries, WWF, and many other non-profit organizations are dedicated to conserving and rebuilding the blue whale population. They use the newest technology to track, study, rescue, and protect the blue whales from extinction. They are also working on adding more regulations and management around fishing, shipping practices, and ocean noise, and more enforcement around whaling.
Today whales are listed as endangered under the endangered species act and are protected from whaling activities under the marine mammal protection act.
Fisheries, NOAA. “Blue Whale.” NOAA, www.fisheries.noaa.gov/species/blue-whale.
“Blue Whale, Facts and Photos.” Animals, National Geographic Society, www.nationalgeographic.com/animals/mammals/facts/blue-whale.
“Blue Whale.” WWF, World Wildlife Fund, www.worldwildlife.org/species/blue-whale.