Comments by "kade 7263" (@kade-qt1zu) on "The Evolution of the Whale" video.

That's due to niche partitioning. Cetaceans with features such as more streamlined bodies and higher nostrils were better adapted for an aquatic lifestyle, giving them a higher chance of survival. This process took place over millions of years, and eventually resulted in the whales we know and love today. As for why gills weren't developed, that's because it's pretty much impossible, for some reason I honestly don't know.
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