The blue whale (scientific name: Balaenoptera musculus) is a marine mammal belonging to the baleen whales (Mysticeti). Up to 31 meters (102 feet) in length and 190 tonnes (210 short tons) in weight, it is the largest extant animal and also is the heaviest known to have existed. But it’s hard to conceptualize how big these wonderful animals really are. To put things into perspective, Facts in Motion channel prepared a video titled “Blue Whales Are Way Bigger Than You Think”. The video also explains the evolutionary reasons behind how and why blue whales get that large.
Some key points from the animation:
Blue whale is the largest animal ever lived
The blue whale is the largest animal of our time and also the largest animal ever lived. That includes dinosaurs and other ocean giants including megalodon and Mosasaur.
It is not the longest animal of all time, though. This title goes to Patagotitan mayorum, the largest dinosaur ever lived, which averaged 122 feet (37 meters) long and was nearly 20 feet (6 meters) high at the shoulder.
The longest blue whale measured by scientists was 29.9 meters (98 feet) long. It was a pregnant female caught in the Antarctic in the 1937-38 season. But there is a lot of circumstantial evidence to suggest that the largest specimens can grow up to 31 meters (102 feet) in length.
Two females measuring 33.6 meters and 33.3 meters (110 feet and 109 feet) were reported, but these were from whalers, not from scientists. So, these measurements should be taken with a pinch of salt.
In general, southern hemisphere blue whales are larger than those living in the northern hemisphere. Also, females are 6% longer than the males.
Average size of the blue whale
Blue whales have an average length of 25 meters (80 feet) and an average weight of 110 metric tons (120 short tonnes). But as explained above, they can get considerably larger than that.
Their organs are also big
Due to its large size, several organs of the blue whale are the largest in the animal kingdom. A blue whale’s tongue weighs around 2.7 tonnes (3.0 short tons) – as much as an African elephant,
The heart of an average sized blue whale weighs 400 pounds (180 kg) and is the largest known in any animal.
They cannot swallow big objects
Despite the gigantic size of its mouth, a blue whale cannot swallow an object wider than a beach ball due to its relatively narrow throat.
Blue whale calves
Even at birth, a blue whale calf weighs about 2.5 tonnes (2.8 short tons) and is around 7 meters (23 feet) in length – already larger even the largest great white shark. During the first seven months of its life, they drink approximately 380 liters (100 US gal) of milk every day. Blue whale calves gain weight quickly, as much as 90 kilograms (200 lb) every 24 hours. Even at birth, they weigh up to 2,700 kilograms (5,950 lb) – the same as a fully grown hippopotamus.
The milk they drink has a very high-fat concentration of about 30%-50%, which is at least 10 times higher than that of human or cow milk. This high-fat concentration gives the blue whale’s milk an almost toothpaste-like consistency.
This has two benefits: first, it makes nursing underwater easier as the milk doesn’t easily dissolve in the water. Second, it provides the necessary nutrients and energy the calf needs to quickly grow large enough to survive the challenging migrations.
In about just 7-9 months, the calf reaches a length of 15 meters (50 feet) and a weight of between 20-25 metric tons making it already larger than any other animal that isn’t whale.
DNA data show that whales are closely related to hippos
According to Jessica Theodor, an associate professor in the Department of Biological Sciences at the University of Calgary, and her colleague Jonathan Geisler, associate professor at Georgia Southern University, DNA information shows a strong relationship between whales and hippos.
The hippopotamus is more closely related to whales than any other land animal.
The smallest baleen whale is the Pygmy Right Whale
Baleen whales range in size from the 20 ft (6 m) and 6,600 lb (3,000 kg) pygmy right whale to the blue whale, the largest known animal to have ever existed.
Blue whales feed almost exclusively on krill, though they also take small numbers of planktonic copepods (a group of small crustaceans). An adult blue whale can eat up to 3,600 kilograms (7,900 lb) of krill in a single day.
The daily energy requirement of an adult blue whale is about a whopping 1.5 million kilocalories (6.3 GJ).
Despite their gigantic size, they have a natural predator
And it’s the orca (the killer whale). Studies report that as many as 25% of mature blue whales have scars resulting from orca attacks. The mortality rate of such attacks is unknown.
Blue whales are endangered animals
The IUCN Red List counts the blue whale as “endangered”, as it has since the list’s inception.
In the Antarctic Ocean, Blue whales were hunted until the 1970s, which reduced their population thereby close to 99.9 percent.
Globally, the blue whale population was reduced from 350-400 thousand individuals at the beginning of the 20th century to less than 5,000 only sixty years later.
Even today, more than 50 years after blue whale hunting banned internationally, they only managed a minor recovery. As a result, only a few specimens now likely exceed 30 meters or 100 feet in length.