I was volunteering at the zoo recently and ended up having one of my favorite kinds of conversations—the kind where someone asks a question that seems simple but opens the door to something bigger.
We were talking about convergent evolution and mangabeys.
Mangabeys are a group of monkeys that scientists originally thought all belonged together because they look remarkably similar. Same general body shape. Similar lifestyles. Similar features.
Makes sense, right? Except… later genetic research showed something surprising. Not all mangabeys are actually each other’s closest relatives.
Some mangabeys are more closely related to mandrills. Those in blue.
Others are more closely related to baboons Those in orange and green. What is even crazier is that the one in green is more closely related to baboons than to the ones in orange. Our species at the Chattanooga Zoo is the Black Crested Mangabey.
Scientists originally grouped them together because, based on what they could observe, it seemed obvious. And then they learned more. Turns out different evolutionary branches arrived at similar solutions.
Why?
Because that body shape works really well for the ecological niche they occupy. Different animals evolving stumbled into that shape and form and teeth and enzyme creating saliva more than once.
That’s convergent evolution.
Once you start noticing it, you see it everywhere.
One of my favorite examples is the Tasmanian tiger. Despite the name, it wasn’t a tiger. It wasn’t even a cat. It was a marsupial.
But it evolved a body plan that looked remarkably similar to placental predators because those features worked for the job.
Different starting points. Similar destination.
The Big Question About Evolution
At that point in the conversation, one of the parents asked me a question I hear a lot: “But how do animals know how to change?”
And I love that question. Because the answer is simple and profound. They don’t. What they do is survive.
Evolution doesn’t have goals. Animals don’t decide to grow longer legs or sharper teeth. Nothing is planning ahead. They just survive.
Every generation's DNA contains variation. Mutations happen naturally. Some help. Some hurt. Most don’t matter much.
If a variation helps an individual survive long enough to reproduce, it has a better chance of showing up in the next generation. If it doesn’t, it tends to disappear.
No intention.
No foresight.
Just survival.
Given enough time and changing conditions, those that survive, may change into different shapes. Sometimes those shapes converge, like mangabeys.
Sometimes those shapes diverge. Like camelids in North America. When the ice age happened it disrupted the climate. Some camelids migrated to Asia to survive and evolved into modern camels. Others headed south and evolved into alpacas and llamas. The ones that stayed in North America - didn't survive and went extinct because of the changing climate. This is why even though this family of animals evolved on the North American continent for 10s of millions of years (there were tall giraffe types, and smaller types and giant ones), we have no camelids in North America anymore. Most didn't survive climate change.
The Joy of Learning
What struck me afterward wasn’t just how interested this family was in the evolutionary biology which is super cool. It was the question I got after explaining how cool mangabeys are and the craziness of their convergent evolution.
How do animals KNOW how to evolve. What shape will work for them?
Because that question—that willingness to say “Wait… how does that actually work?”—is something I deeply admire.
That father could have nodded politely and moved on. Instead, he got curious. And curiosity changes everything.
Humanism, to me, starts there. With the recognition that the world is under no obligation to match our assumptions.
Sometimes what looks obvious turns out not to be true. Scientists thought mangabeys were all one close family. They asked more questions and learned otherwise. And what they learned was even more amazing than their predecessors could have imagined.
I’ve been interpreting for our black crested mangabeys for a year. I only learned their evolution recently. I volunteer at the zoo all the time and I still discover things I didn’t know.
That’s not failure. That’s the joy of learning.
The world is full of things we think we understand. Until we ask one more question.
So stay curious.
Ask the question.
Be willing to discover you were wrong.
Be excited when reality turns out to be more interesting than you expected.
Because learning isn’t evidence that you didn’t know enough before. Learning is evidence that you’re paying attention. And that, to me, is one of the best parts of being human.
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