The biggest whale is the blue whale which also happens to be the biggest living animal in existence.
In fact the largest blue whales can measure in at over 100 feet in length and weigh as much as 150 – 200 tons when it is fully matured.
Even a baby blue whale is massive in size compared to many other species of whale.
At birth baby a blue whale can measure in at around 25 feet in length and will continue to grow very quickly during its first few years.
During the first year of birth the baby blue whale can gain as much as 200 pounds per day and consume 100 gallons of milk every 24 hours.
In comparison to the blue whale the largest living land animal (overall) is the African bush elephant, which can reach a maximum height of 13.8 feet and weigh as much as 27,000 pounds.
The largest flying bird in the world is the Andean Condor which has a 10.5 foot wingspan and weighs in at around 26 - 33 pounds.
Despite being the largest living animal in the world the blue whales diet primarily consist of krill (a small crustacean that generally measures in at mere 1 – 2 centimeters in size, however a few species can grow to lengths of up to 6 inches).
To provide them with the energy they need to thrive and survive blue whales may eat as many as 40 million krill per day.
In addition to krill blue whales may coincidentally end up consuming fish and other small sea life while hunting for and engulfing krill.
Another interesting fact about the blue whale is that during long migration trips a blue whale may completely forgo eating for as long as 4 months living primarily off of their stored body fat/ blubber, which they use for energy.
Even with their simple diet and fasting migration periods blue whales manage to be impressively large.
Part of the reason these marine mammals are able to grow so large has to do with the fact that water provides them with bouncy, which makes it easier for whales to move around regardless of their size.
The ocean is extremely large and expansive allowing blue whales to swim around without having to worry about colliding with nearby objects.
The waters bouncy also helps support the whales large organs which would be crushed under the weight of gravity that we face as land dwelling creatures.
In addition to supporting the whales large size the ocean also provides whales with a nearly limitless abundance of food, which would be extremely scarce on land for an animal of their magnitude
Note: The largest blue whale ever recorded measured in at around 110 ft. in length, although there have been claims of a blue whale measuring in at 115 feet in length.