Blue whales are perhaps one of the most magnificent creatures of this planet. Their sheer size and incredibly peaceful lives are sure to fill anyone with wonder, astonishment and immense respect, even if they are not generally animal lovers. Even though they are such big animals, very less information has been found about them and many things, behavioral and physical, still remain a mystery. But, what little we know is still enough to amaze us. So, here are some facts about blue whales that we are sure you would enjoy reading about.
1. Even when taking dinosaurs into account, the modern day blue whale is the largest animal to ever exist on Earth.
The sauropods, with their long necks that could reach tree tops and their long tails, are considered the largest of dinosaurs. From the tip of their mouths to the tip of their tails they measure between 80 to 130 feet and can weigh up to 96.4 tonnes. Blue whales, on the other hand, measure up to 98 feet to 106 feet long with the maximum recorded weight being 173 tonnes, and might probably reach 181 tonnes. Compared to blue whales, sauropods are skinnier and weigh much less.
It is possible that being in water has enabled whales to maintain their large size without bearing the brunt of gravity, an influencing factor in the evolution of land animals. Their large fat filled bodies enjoy buoyancy in water which prevents them from collapsing under their own weight.(1, 2)
2. A blue whale’s tongue weighs as much as an African forest elephant and its heart is at least the size of a golf cart.
The largest of animals has the heaviest of tongue and weighs around 2.7 tonnes, which is around the same weight as an African forest elephant, though largest of these elephants are known to gain as much as 6 tonnes. Though there are claims that a blue whale’s heart being as big as a car, so far they could not be verified considering the difficulty in obtaining a proper specimen that was intact. The one time researchers could find a 76.5 feet blue whale that died after getting trapped in ice in Canada, the heart they cut out was the size of a golf cart. Whether a whale bigger than that could have a heart the size of a car is not known.(1, 2, 3)
3. Blue whales can consume 500 kilograms of krill in a single mouthful and get half a million calories from it. That’s 200 times of what they spend in the act.
Blue whales feed almost entirely on krill, small shrimp-like creatures, and a small number of copepods, small fish, crustaceans and squid that get into their mouth. The mouths, when fully expanded, are large enough to hold 90 tonnes of food and water. During their feeding time, they open their mouths wide and lunge at the krill. Then they close their mouths and push the water out through baleen, the bristle-like structures made of keratin present on the edge of upper jaws.
If the krill swarm is dense enough, an adult whale can swallow up to 500 kilograms of krill, that’s 457,000 calories, in a single mouthful. In a day, an adult whale can eat up to 40 million krill. They usually lunge only at big swarms because when they open their mouth, the water slows them down almost stopping them. So, small swarms are not worth the energy they would have to spend.(1, 2)
4. Blue whales are seasonal feeders. They can go up to 6 months without eating when they migrate for breeding.
The largest populations of krill are found in the Antarctic and constitute the main food source for seals, penguins, fish, squid, as well as whales. The blue whales gorge on Antarctic krill during feeding season. As they gain more energy than they spend they build substantial energy reserves. They spend these reserves when migrating for breeding to warmer parts of the oceans near the equator, where krill is scarce.(source)
5. Blue whales are born huge as well. Their calves weigh 2.5 tonnes at birth, gain 8 lbs per hour and grow at a rate of 1.5 inches per day!
The female blue whales typically give birth every two or three years at the start of winter and have a gestation period of 10 to 12 months. Their calves weigh about 2.5 tonnes at birth and are 7 meters (23 feet) long. In a day they drink about 380 to 570 liters of milk, which has an energy content of 4,370 kilo calories per kilogram. The calf doubles in size in just six months by which time they are weaned.(1, 2)