The blue whale is known to be the largest mammal for many reasons. We can list some significances of its size:
1. Large heart
Blue whales have large hearts that contribute to the circulation of blood throughout their bodies. This way, oxygen and the necessary nutrients are efficiently and properly distributed.
2. They are predators
The size of blue whales help to consume smaller organisms more quickly, as they are filter feeders and prey on smaller fish such as plankton. The energy provided by these small organisms helps to sustain the large bodies of the blue whales.
3. Evolution
Over extensive periods of time, blue whales have evolved in a way that allows for the sustenance of their large sizes.
While these and many other factors have led to the enormous size of blue whales, it's important to consider that their sizes are the result of different biological, embryological, and environmental adaptations.