Image from How Stuff Works
In 2019 I read every article published by Science, the preeminent publication of the American Association for the Advancement of Science and the coolest scientific journal in scientific journal school (Nature is the bad boy). Ok, alright, I only read (skimmed) the tables of contents for each issue BUT I did put eyes on all 51 of them. Please clap. This was all for another project, but I mention it now because I came across some pretty rad stuff while slogging through a lot of articles about qubits and graphene and chirality. What rad stuff? Let’s talk about whales (again, and again, and again).
Specifically, why they’re so gosh darn big. Did you know that the blue whale is the largest creature on the planet, not just now, but ever? Yes, it is bigger than any dinosaur and it is alive right now. Spell it: R-A-D. But it’s been something of a baffling paradox as to why this is the case – especially given that blue whales, along with the other species of large whales, feed predominantly on tiny tiny crustacean prey. They do this by taking large gulps of sea water (their heads and throats make up 1/3 – 1/2 of their body) and filtering out their prey with specialized “teeth” – the baleen plates. This method of eating takes a lot of energy, but that’s a-OK because it turns out it’s quite efficient at capturing a huge quantity of high quality food, allowing these whales to reach their massive size.
As to why they don’t grow bigger? These Science scientists believe it has nothing to do with the whales’ body plan or feeding strategy, but is instead dependent on availability of prey. The whales are feeding primarily on seasonal swarms of krill and other prey that are abundant for only part of the year. If those prey were somehow more concentrated geographically or available year round, we might see even bigger whales. That’s absolutely nuts that it’s not organ size or blood circulation or physics of some kind limiting these creatures to only gargantuan size – just food. Remember, though, it’s not your size that matters, it’s how rad you are. Baleen whales just happen to be doubly blessed.