There is cause to believe that climate change is the reason why whales have grown to be so massive in size.
According to a recent study, whales grew to be an average of 30 meters long roughly 4.5 million years ago, a blip in the overarching timeline of our planet. In order to fully grasp the significance of this number, though, we must examine what was occurring on Earth during this time period— that is, the beginning of the first ice ages, otherwise known as Pleistocene Epoch.
During Pleistocene Epoch, it is believed that liquid runoff from glacial expansion deposited nutrients into the oceans, much of which was consumed by krill and other smaller animals that whales fed off of. Due to the fact that climate change had caused many larger sea animals to disappear in the wake of the plummeting temperatures, this created a much patchier pattern of food availability. That being the case, whales would consume these explosively growing smaller animals during abundant seasons of the year, fueling their own growth and ensuring that they could survive in the changing world whilst other large animals went extinct.
With regard to evolution, these 30 meter-plus whales have larger mouths and are much more quickly able to move through packs of prey, ensuring that they can consume their food in the most efficient manner possible. This ultimately ensured their survival in the grand scheme of things. Though it was initially believed that whales had gotten so huge in order to consume mega-predators and, therefore, cement their spot at the top of the food chain, scientists now know that this was simply a beneficial side effect of their initial growth spurt fueled by a need to survive an increasingly hostile environment.
Although it can now be reasonably concluded that climate change triggered such a growth in whales, it is unclear how 21st century climate change has been and will be affecting whales in the coming years. Due to the fact that even the most minute temperature increases can throw oceanic ecosystems into chaos, it seems a likely (and terrifying) assumption can be made that climate change, the very thing that helped whales survive ancient temperature changes in the first place, could very well be their undoing.
Natalie Wickstrom is a freelance writer based in Athens, Georgia. She most likely wrote this piece to the tune of a movie score whilst chewing gum.