Among the most massive living animals on Earth today are blue whales, but have you ever stopped to think about how they became so large in the first place?
Rewinding 50 million years into the past, you wouldn’t find any animals as large as the blue whale. In fact, nothing even came close. Blue whales only recently evolved to become as large as they have, and their environment played a significant role.
After their ancestors began retreating from land to the sea, they were no longer impacted by the technical size limitations imposed by gravity. With their enormous appetites and stout size to start with, it wasn’t long before these factors helped the blue whale’s ancestor grow larger under the right conditions.
As time went on, larger whales found it easier to avoid predation than their smaller counterparts. These larger whales also sported larger mouths, enabling them to eat more at a time, which further contributed to their size today.
Without a doubt, natural selection played a significant role. Intriguingly, the blue whales that exist today are thought to be some of the largest in all of Earth’s history.