The average basal metabolic rate (BMR)  of a 100 ton blue whale is around 25 kilowatts per hour, when compared to a human with a BMR of 1.9722 kwh, its clear to see that even when resting the BMR of a blue whale is incredibly high. When you take into account the whale is 100 feet long and 100+ tons its clear to see why even at rest it takes a lot of energy just to survive. 

​

BMR only shows us the metabolism of the whale when at rest, SMR or the Standard Metabolic Rate shows us the metabolic rate of the whale when it is in motion doing its day to day traveling. The SMR of blue whales has never been recorded in a study but has been estimated to nearly 10 times that of their BMR. 

​

To put things into perspective, in the nutrition page (hit the button below to go there)  it is stated that a blue whale needs to consume upwards of 480 million calories per day in order to survive. Each dive for food can cost the whale upwards of 1900 calories per lunge and the whale can lunge up to 6 times per dive which means the whale burns 11,400 calories per dive. 

​

 

This is a huge expenditure of energy for the whale and is only favorable if the food source is rich in calories which the krill they eat are. This leads to an incredibly energy efficient hunting pattern with the whale being able to taker in upwards of 2.7 million calories per dive, while only burning arounds 11 thousand. Which is incredibly efficient in the grander scheme of things. 

​

The sheer size of a blue whale plus the fact there are moving through a medium with much mote friction then air, means they expend a crazy amount of energy just to move however, the caloric density of each mouthful of krill is so high that they gain 200 times more calories then they burn per mouthful.