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The Diet of a Blue Whale

Ishani Chatterjee Shukla
Ever wondered what the largest creature on earth eats? Well, once you get to know the details of the blue whale diet, you'll be amazed as well as amused.
Blue whales - the largest creatures to have ever existed, whether living or extinct - way larger than even the largest dinosaur that ever walked the Earth! That makes me wonder if smaller creatures like ants or insects appear invisible to these leviathans of the ocean, like bacteria and other micro organisms appear to us!
Well, pardon my random spell of fascination - once you get to know more about these gigantic creatures you'll probably feel a little dazed yourself for a few ensuing moments! Now, before we embark upon discussing blue whales diet and feeding habits, let me share an interesting fact with you.
Whales are classified into two broad groups based upon their feeding mechanics and related feeding technique. These two broad sub groups into which whales are divided are toothed whales and baleen whales.
Now, as the name suggests, toothed whales have two rows of teeth, one row in each jaw, with which they catch their prey and which they use to grind their food with, in order to feed. On the other hand, baleen whales indulge in what is known as filter feeding.
Baleen whales' mouths are equipped with a feeding structure known as baleen or whalebone which are flat, plate like things that hang from the roof of the mouth in two parallel rows, acting as comb-like filters which trap small shrimps and fish when the whale swallows in and presses out sea water from its mouth.
Blue whales are baleen whales and they filter feed on small sea creatures using the whalebone structures in their mouths.

Blue Whale Diet and Feeding Habits

If you have taken any hint from the blue whale fact given in the introductory segment, you must have inferred by now that blue whales are not aggressive hunters and they feed on small ocean creatures that swim inside their mouths along with the water that they swallow in. So what does a typical blue whale diet menu consist of on an average day of feeding?
Well, krill ranks as the top favorite in the average blue whale feeding menu. In case you're wondering, a krill is a shrimp like creature which inhabits oceans all around the world.
These crustaceans swim in the waters in huge swarms and in a single day, a blue whale eats approximately 8000 pounds of krill, which comes to somewhere around 40 million units, in a single day! No points for guessing that blue whales are most active in those parts of the ocean where large concentrations of krill are found!
Apart from krill, blue whales may also feed on copepods which are tiny crustaceans which look somewhat like over sized mosquito pupae and these are found in oceans and seas as well as fresh water.
Most ocean dwelling copepods are found in very deep water and close to the ocean floor. All said and done, krill compose of 90% of a blue whale's staple diet on any given day.
That was all about their diet. Blue whales are cold water-dwelling marine mammals and the cold currents of the Arctic and Antarctic oceans act as natural blue whale habitats. Unlike dolphins, porpoises or other baleen whale species, blue whales do not move around in large social groups. They are mostly found in pairs or small groups, even solitary.
However, in regions with large concentrations of krill, as many as 50 blue whales can be found all over a large oceanic area, though they do not form a close-knit group and retain their separate individual or pair identities among the huge gathering. A fully mature adult blue whale measures about 33 meters from tail to tip and weighs around 200 short tons.
They can swim very fast for short bursts of time, reaching a speed of more than 50 kilometers per hour at times! Whew! All this by just eating crustaceans? Wonder what an all-lobsters diet would do to us humans then!