It’s Always Curved to the Left

So it curves a little to the left? So what? That doesn’t necessarily mean anything, right? I mean, everyone’s does a little bit. What’s that? There’s an entire class that doesn’t curve and is perfectly symmetrical? Okay, now I’m just getting weirded out. What do you mean don’t worry about it? All of our ancient ancestors curved too? It’s just an adaptation to help my species survive? Oh, okay then, no problem.

If it helps me find food, I won’t argue.

That confusing piece of literature was the thoughts of a Odontoceti (toothed) whale. His snout curves a little bit to the left in order to help him produce and hear high frequency sounds used for echolocation, a type of whale sonar that helps them find lunch. Scientists always assumed that the slight curve was a modern adaptation to help with the high frequencies.

That is, until paleontologists got their heads out of their asses.

There are plenty of ancient whale skulls from the ancestors of all whales known as archaeocetes. And there are plenty of examples of their skulls curving a bit to the left. However, scientists always just assumed that the slight deviations were due to the common pressures that underwater bones go through during fossilization.

But then, Julia Fahlke, a postdoctoral fellow at the University of Michigan, began research into how these ancient whales used their teeth. Unlike modern whales, the ancient ancestors used theirs to chew their food.  Modern whales just bite it and swallow or use giant filters called baleen to suck tiny bits of food from the ocean. By studying wear patterns on the fossilized teeth, Fahlke hoped to study the transition from chewing to swallowing.

After getting a 3D computer model of the whale skull being studied, she digitally fixed the skull so that it was perfectly symmetrical. But she just couldn’t get the jaws and teeth to line up correctly. Then it hit her. The damn thing was supposed to be asymmetrical.

She immediately hit the fossil collection at UofM and did an analysis on six other skulls. Sure enough, the average of their curvature was great enough to be considered a significant deviation. What’s more, on further analysis, she discovered the skulls also twisted a bit, making them even more asymmetrical.

This is a pretty common adaptation for animals in order to help with directional hearing. Owls, for example, have asymmetrical ear holes to help differentiate rustling leaves on the ground from those all around them. Put together with other adaptations the ancient creatures show for low-frequency hearing, it seemed pretty obvious that this was just another adaptation for directional hearing.

Meaning that ancient whales had asymmetrical skulls, as do modern toothed whales. But as modern toothed whales developed their form of sonar, they lost the ability to hear low frequencies. The twisted skull was the starting point for the sonar, though.

As for the baleen whales, they’re skulls seem to have been the ones to adapt, becoming symmetrical as they no longer needed either form of hearing. They just suck in a ton of water and figure out if there’s food in it later.

And they don’t hear shit.

Speaking of echolocation, here’s a fun fact—people can do it too. Check out the amazing video below and think about this; if the world quickly lost its vision, don’t you think the people who could do this type of thing would do much better in the world? And that whatever the hell this guy has that allows him to do this would quickly spread and become more pronounced in the population?

That’s evolution, baby.


About bigkingken

A science writer dedicated to proving that the Big Ten - or the Committee on Institutional Cooperation, if you will - is more than athletics.
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