Kolkata, West Bengal
I wanted to include the word “fish” in the title of my piece. After all, we are accustomed to calling almost every aquatic creature a fish without hesitation. Besides whales, we have starfish, seals, and even the very familiar shrimp that we refer to as fish. Following that pattern, I could have called it a “whale fish” too. I didn’t because this is a scientific article. Science has concluded that a whale is not a ''fish''. If it's not a fish, then what is it?
The answer from science is that a whale is a mammal. This explanation has been expanded so much in textbooks that it almost seems like if it’s not a fish, it must be a mammal. However, this understanding oversimplifies things. In the evolutionary journey from single-celled organisms to humans, there are five major classifications: fish, amphibians, reptiles, birds, and mammals. They all fall under the vertebrates. Except for mammals, all are hatched from eggs. These categories are associated with specific characteristics—like, amphibians can live in both water and on land, and birds can fly—something like that. But it raises the question, why can’t an amphibian or a bird drink its mother’s milk? Thus, an amphibian’s or a bird’s ability to live in two places or to fly is not their defining characteristic. Every class of life evolved by acquiring a primary feature.
The whale possesses features that place it at the highest level of evolution, yet it hasn’t been able to leave its aquatic habitat. Externally, it looks just like a fish. That’s why we instinctively want to call it a “whale fish” when we see it.
There are many species of whales. The size of a whale varies depending on its species. But since we are initially awed by the whale’s enormity, we are most eager to discuss the largest—the blue whale. Blue whales can reach up to a hundred feet in length and weigh as much as seven elephants. The smallest species of whale is about ten feet long. Why isn’t such a massive creature, like the blue whale, found on land? It is the king of the waters. But when it comes to food, it has no choice but to feed on tiny shrimp-like creatures. Some can eat small fish. This is because their mouths are equipped with a bony sieve known as a “Baleen Plate,” through which large fish cannot pass. So, even though it sees a variety of fish swimming around it, the whale cannot eat them—just like a diabetic surrounded by jars of sweets. This is the case with eating; now let’s talk about sleeping. It can never sleep peacefully. No, its sleep isn’t interrupted by the fear of enemies. Who would dare to attack a whale! The real problem lies in its breathing. Unlike other aquatic creatures, it has no gills; instead, it has lungs, a more sophisticated organ than gills. But what good are lungs if they cannot function underwater? Thus, the whale must surface every now and then. And due to this, predators can track its location. Hunters, driven by greed for whale meat, blubber, and bones, mercilessly hunt whales. A sharp harpoon strike would not be enough to kill it. But since the whale has to surface to breathe, humans, being fellow mammals, exploit this weakness and repeatedly strike until it succumbs. One might wonder, if whales lived on land, would humans be able to kill them like this?
Then, why didn’t whales try to live on land? Other creatures have gradually evolved lungs over millions of years and moved onto land. Some even transformed their limbs into wings and conquered the skies, creating the grand category known as birds. Will the whale remain forever in the water?
Let’s look at it from a different perspective. Other creatures strove to adapt to life on land. In that endeavor, they replaced their gills with lungs. But whales’ ancestors always had lungs. They walked on four legs and lived on land. What drove them to make the seemingly anti-social decision to live in water? We cannot say for sure. But nature did not pour water on their plans; rather, it facilitated the transition as much as possible. It transformed their front limbs into flippers for swimming and made their hind limbs disappear entirely. Yet, nature did not replace their warm blood with cold blood. Instead, it created a thick layer of blubber under their skin to reduce heat loss.
All this happened over millions of years. If, in another few million years, they develop gills alongside or in place of lungs, they will no longer have to surface frequently and lose their dignity in front of humans. But one wonders, would that be a matter of pride for a grand creature like the whale? Could we truly call it evolution, or would it be a form of regression? Ultimately, the unfortunate whale would have to bear the burden of this exceptional anomaly of nature.
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