Featured Image Credit: Wild Horizon / UIG via Getty Images via NBC News
Let’s start off with a little fun fact, shall we? A blue whale weighs in at a whopping 300,000 pounds, making it the most massive and heaviest creature roaming the ocean. You may have known that, but if you didn’t, you’re welcome!
What I bet you don’t know, is WHY? Why are whales so dang big? Not even scientists have an answer, and that’s definitely saying something.
However, one group of researchers offer an interesting theory in Proceedings of the Royal Society: Fusing the fossil record and phylogenetic work, they found that whales probably became as large as they are now only 3 million years ago- and climate change could have been the reason behind it. Which leads us to all wonder..with the current climate change, warming and acidifying oceans…what does that have in store for the future of these gentle giants?
Fossil records show that ancient whales are not even close to being as big as whales are today. Baleen whales have been around for more than 30 million years. But for most of that time, they were topping out at 30 feet or so, about one-third the length of the modern blue whale. Being small had its advantages, but not for very long.
When the ice age began some 3 million years ago, ice sheets expanded in the north and the runoff dragged nutrients into the sea. An increase in wind-driven upwelling (which occurs when wind pushes surface waters off-shore and causing deeper ocean waters underneath surface waters to replace it) brought even more nutrients up from the depths to the surface. This resulted in blooms of plant-like phytoplankton..which led to blooms of krill that fed on this phytoplankton. The bigger whales were simply more efficient at eating all of these new-found nutrients, beating out all of their smaller cousins.
“We think that kind of ecological explanation underpins why we see this shift in body size,” says paleobiologist and study co-author Nick Pyenson of the Smithsonian. “Not just the origin of the very big whales, but the extinction of very small baleen whales…”
“It’s not true that as soon as whales got into the water they got very, very big – as big as a blue whale,” said Pyenson. After all, baleen whales lived in the water for tens of millions of years before growing into the giants they are today.
What this research makes clear is that climate change could be the answer for why whales ended up becoming so massive. They had to adept and adjust during a time when the world and their environment was changing drastically. While it’s still too early to tell how it will affect them in coming decades, changes in ocean temperatures may have devastating consequences. Climate change made these giants, and now it is threatening their very existence.