At some point, you’ve probably wondered, what is the biggest animal in the world?
The blue whale is the biggest animal in the ocean, its body reaching lengths of up to 80-110 ft (24.4-30.5 m). Despite their enormous size, these gentle giants feed entirely on krill, filtering the small animals from the water.
Blue whales are deep divers who prefer cold ocean temperatures. They are mostly solitary, but they frequently communicate with one another, producing sounds they can hear from hundreds of miles away.
What Is The Biggest Sea Creature?
The blue whale is the largest animal in the world, both on land and in water. Their massive bodies can grow about 80-110 ft (24.4-30.5 m), and they weigh about 200 tons (181,437 kg).
There are five subspecies of blue whale and those living in the Antarctic tend to grow much larger than the other subspecies.
Females also weigh more than their male counterparts, reaching up to 108.3 ft (33 m) in length and up to 209.4 tons (190,000 kg). Males only grow up to 95.1 ft (29 m) and 165.3 tons (150,000 kg). At birth, a blue whale calf is usually about 22.9 ft (7 m) in length and only 2.9 tons (2,700 kg).
A blue whale’s size is approximately equivalent to that of 33 elephants — the largest land mammals. A blue whale’s calf is about the same weight as an adult African elephant.
Their bodies are long and streamlined, with a mottled gray or blue color covering their back. Their undersides are lighter. The head can be up to a quarter the length of their body. The heads are long, but broad, and have an arch in the shape of a “U”. Their tongues weigh about as much as a single elephant.
Not surprisingly, their hearts are massive; about the size of a Volkswagen Beetle. The major blood vessel inside the heart is even so big that a human baby could crawl through it.
Blue whales are long-lived animals, often living up to 90 years old. The oldest blue whale ever recorded lived for 110 years.
- Common Names: Blue Whale, Antarctic Blue Whale, Great Northern Rorqual, Sibbald’s Rorqual
- Origin: Alaska, West Coast, Southeast, New England/Mid-Atlantic, Pacific Islands
- Length: 80-100 ft (24.4-30.5 m)
- Weight: 200 tons
- Lifespan: About 90 years
Habitat
Blue whales are deep divers, and because their populations are so small, we rarely see them. They live in every ocean around the world except the Arctic.
The Whale and Dolphin Conservation (WDC) describes their distribution:
“Preferring to live in deep ocean, blue whales are rarely seen close to shore. In the Northern Hemisphere, they can be seen in the northeast Pacific, from Alaska to Costa Rica, and migrate towards the northwest of the Pacific too. In the North Atlantic Ocean, blue whales can be found near Greenland, Newfoundland and Nova Scotia. In the Southern Hemisphere, small populations remain in the Antarctic, as well as parts of the Indian Ocean.”
Diet
As the biggest creature in the ocean, the blue whale needs to eat a lot. Remarkably, the biggest animal in the world feasts on one of the smallest animals in the ocean.
They feast on Antarctic and ice krill, which are small, shrimp-like crustaceans. They need to eat about four tons of krill a day, which equals about 40 million individual krill. Their stomachs can hold about one ton of krill at a time, so they need to eat multiple times a day.
While some species of whales have teeth, blue whales do not. Instead, their mouths are full of over 800 black baleen plates, a hair-like substance that hangs from the whale’s mouth in a curtain.
To feed, they suck in a large gulp of water, then close their mouths, pushing the water back out. As the water filters back into the ocean, the krill remains, and the whale swallows it.
Blue whales are rorqual whales, meaning they have 55-68 pleated throat grooves that run from the throat to their naval. The grooves expand when the whale inhales water during feeding.
Behavior & Temperament
Blue whales are constant migrators who travel remarkably long distances. The whales form groups, called pods, to migrate. During the summer, they migrate north in search of krill that lives in colder waters. During summer, they migrate back to warmer waters to breed.
Migrating takes a long time and copious amounts of energy, but blue whales eat little during migration. Instead, they rely on the energy reserves from their blubber, often going as much as four months without eating.
When they are not migrating, blue whales are usually solitary animals, though they may swim in small groups.
They are fast swimmers, usually traveling at speeds of about 5 mph (8 km/h). When they need to go somewhere fast, they can swim at speeds of up to 20 mph (32.2 km/h), but they can only withstand this for short periods of time.
Not only are blue whales the biggest animal on the planet, but they are also the loudest animal. Their call can reach 188 decibels at its loudest, while a jet engine only reaches 140 decibels.
Blue whales use their calls to communicate with one another. One such call, a low-frequency whistle, is likely meant to attract other blue whales. They also communicate using a variety of groans, moans, and pulses.
Reproduction
Blue whale reproduction is slow because the gentle giants only birth one calf every two to three years.
The gestation period is 12 months, and after the calves are born, they stay with the mother for another seven to nine months. The mother and calf build a strong bond, and the calf rarely strays from its mother’s side. Reliant on their mother for survival, a blue whale calf can drink up to 66 gal (250 L) a day.
Sexual maturity of blue whales is likely between 5-15 years of age.
Predators
Because of their sheer size, blue whales have almost no predators. There is one exception though: the orca.
It’s rare, but some subspecies of orcas include whales as part of their diet. To take down such a large animal, orcas must coordinate an elaborate attack as a group. The orcas work together to surround the whale from the front, sides, and bottom so it has no means of escape.
After surrounding the whale, orcas take turns biting the whale until it becomes so wounded it can no longer fight or flee.
For an easier kill, orcas may attempt to separate calves from their mothers as well.
Conservation
The International Union for the Conservation of Nature (IUCN) assessed the status of the Blue Whale in 2018. They listed them as “endangered”, but with an increasing population. Estimates show that there are about 10,000-25,000 individuals left in the world.
Whale Hunting
Their populations dwindled so quickly because of direct exploitation. People have been hunting whales forever, but their falling populations came because of modern whale hunting. Modern whale hunting began in 1868 in the North Atlantic, where sailors would use harpoon cannons mounted on their ship decks.
Worldwide legal protections banned whaling in 1966, but by the 1960-1970s, the blue whale populations were likely down to the low hundreds. Since we put protections into place, the blue whale populations have steadily begun increasing.
Nets & Fishing Gear
While blue whales are no longer hunted, they still face threats from commercial fisheries. Fisheries commonly use trawling nets. Trawls are large nets that drag along the bottom of the ocean, catching anything in their paths. They often impede blue whales and pose a threat.
Ship Strikes
Today, the biggest threat to blue whale populations is ship strikes. Those inhabiting their calving grounds near southern Sri Lanka seem to be hit more frequently. Whales struck by ships experience blunt force trauma, and they often leave those that live with permanent swimming problems.
Noise Pollution
Noise pollution is another threat because blue whales use sound to communicate with one another and to navigate waters. Noise from ships, oil drilling, and military sonar can all interfere with a blue whale’s hearing, making them confused.
Pollution & Climate Change
Their primary food source, Antarctic krill (Euphausia superba) and ice krill (Euphausia crystallorophias), is likely to dwindle during the 21st century, too. Climate change is reducing ocean productivity, leading to fewer krill reproducing. Rising ocean acidity is also limiting their ability to build shells.
Besides their food being compromised, whales themselves face threats from pollution. The chemicals in the water may have negative impacts on their fertility.
Conservation
Despite all these threats, organizations and governments are working to put more protections in place.
The National Oceanic and Atmospheric Administration (NOAA) describes its efforts in protecting blue whale populations:
“NOAA Fisheries and its partners are dedicated to conserving and rebuilding blue whale populations worldwide. We use a variety of innovative techniques to study, protect, and rescue these endangered animals. We engage our partners as we develop regulations and management plans that foster healthy fisheries and reduce the risk of entanglements, create whale-safe shipping practices, and reduce ocean noise.”
Conclusion
The largest sea creature is the blue whale, reaching lengths of up to 80-110 ft (24.4-30.5 m). Because of their size, you’d think blue whales would be formidable predators, but they feed solely on tiny krill they filter from the water.
Blue whales are excellent communicators, their voices traveling for hundreds of miles. They swim together in pods when migrating to their breeding and feeding grounds. Females even make excellent parents, protecting their calves for up to nine months until they are old enough to wean.
FAQs
Blue whales are the largest animal on earth and land. But they are not only the largest animal alive today. They are also the largest known animal to have ever existed.
The largest dinosaur to have ever lived, the Argentinosaurus, even pales compared to the blue whale. Argentinosaurus weighed just 110 tons (99,790.3 kg).
Researchers believe the yokozuna slickhead is the largest deep-water fish in existence. Only having been captured six times, researchers know little about this fish. We have caught these fish at depths of about 6,562 ft (2,000 m), and the largest individual was 4.5 ft (1.3 m) long.
Blue whales do not have teeth. Instead, they have over 800 plates of baleen. Baleen looks like thick hair and acts as a sieve to filter water from krill.
There is no record of a blue whale being violent toward a human, rather, people term them “gentle giants”. Even if a blue whale wanted to eat a human, they couldn’t because their throat is too small.
