Why are whales so big?
It turns out it's not at all because large size allowed them to survive encounters with predators with greater probability.
Paleontological facts (sizes of skeletons of whales that lived earlier) show that for tens of millions of years, whale sizes did not exceed a "very modest" 10 meters, which is 3 times smaller than the length of a modern whale, and the mass difference was even more noticeable.
And no influence from the entire pack of predators roaming back and forth during all this time led to an increase in the size of plankton lovers.
And only in the last 4.5 million years ago did a race suddenly and "unexpectedly" begin - who's bigger. This is roughly like if our ancestors for two million years did not exceed 60 cm in size, and then suddenly over the last three hundred thousand years instantly grew to the size of modern humans.
"And here's what changed during this time: the first ice age began. Life became seasonal: during the short summer, meltwater carried many delicious things into the ocean, stimulating plankton reproduction. And then immediately autumn, and that's it" – no food.
"In short, whales faced the task of feeding as efficiently as possible in a couple of months." And when there's a lot of plankton, the bigger the mouth, the more you can devour. The more you devour, the more fat reserves you have, which allow you to survive the hungry times. Therefore, "becoming big was the only way out for whales: those who failed to do so did not survive the ice age."