Are Humans Monkeys After All?

Sustainability. It’s everywhere, isn’t it? Turn on a screen, open a paper, half the conversations seem to orbit around it. It’s on most minds most of the time these days, or at least people feel like it should be. The trouble is, the concept itself is so sprawling, so broad. Maybe that broadness puts some away from actually engaging with it. It certainly comes with multiple facets, and is full of rules and experts out there telling real people what ought to be done. Fix this, change that, buy this, don’t do that, bla-bla-bla… I’m not too sure what ought to be done.

Okay, so with that cloud of general confusion established, I’ll just pile my own thoughts onto the heap. Let’s look at something seemingly different, maybe even simpler, but which connects back in ways that feel important.

It’s a question from biology, about where we fit in: Are humans monkeys?

Now, hold on. Because the way people react to this question, the pushback it gets, reveals something quite interesting about how we humans tend to view ourselves. I’ve noticed it, this immediate recoil. “No, we evolved from them, but we’re not monkeys now.” Or, “Look how different we are, our brains, our tools, our iPhones!” There’s this deep, almost visceral need to draw a line, to say, “That’s them, this is us.” As if we’ve somehow transcended our biological heritage, graduated from the messy tree of life onto some separate, self-made platform. There’s also that lingering image of evolution as a ladder, with us perched triumphantly at the top, and everything else just less successful versions of us, maybe? Stuck on lower rungs.

Now, that view, the ladder idea aiming for humanity, doesn't quite square with how biology seems to work, from what I understand. Evolution feels more like a vast tree, with countless different branches thriving in their own ways. But still, that ladder image, it seems to hang around in people's minds.

So, why this particular conversation about the 'monkey' label specifically? It makes you wonder. It looks like this whole classification thing isn’t always 100 percent comprehended, or maybe the implications aren't always thought through. I do see, though, at least from what I observe in my own little bubble of conversations and reading, that many people probably get bits of it, maybe a 50 percent grasp, if they've really looked into it. And it makes me think, that this is the sort of question that everybody should know how to respond 100 percent.

Okay, I’ll first give my attempt at responding and then come back and explain why I consider it so important that this is responded.

The way biologists categorize life these days relies heavily on tracking evolutionary lineages, family trees basically. The standard approach is to group organisms into ‘clades’. A clade is simple in principle: you take an ancestor, and you group it together with all of its descendants. Nothing gets left out. Think of it like a complete family history starting from one couple; everyone who descended from them is part of that group, no matter how different they become generations later. You don’t just decide to cut off a branch of the family tree because they developed strange habits or look different now. If you do that in biology, leaving out some descendants, you get what’s called a ‘paraphyletic’ group, which isn’t considered a complete picture of the evolutionary relationships. The goal is usually these complete ‘monophyletic’ groups, or clades.

So, let’s trace our own lineage briefly within the primates, applying this idea. Primates are one big clade. Way back, this group split. One branch gave rise to the ‘wet-nosed’ primates like lemurs and lorises. They often rely more on smell, and they can make their own vitamin C. The other branch, the ‘dry nosed’ primates or Haplorhines, includes tarsiers, monkeys, apes, and us humans. We can’t make our own vitamin C. Why? Because we all inherited the same specific broken gene for vitamin C production. This tells us the break probably happened just once, in an ancestor common to all of us dry-nosed folks, after the split from the wet-nosed branch. It’s a shared inherited flaw, defining our clade.

Within the dry-nosed group, after the unique tarsiers went their own way, the rest are called Simians. This basically covers all monkeys and apes. The Simians then split again. One group evolved in the Americas, the ‘New World’ monkeys. They have distinct features, like sideways-pointing nostrils and sometimes grasping tails. The other group evolved in Africa and Asia, the Catarrhines, the ‘down nosed’ primates.

Now, these Catarrhines split again. One line gave us the ‘Old World monkeys’ like baboons, macaques, and their relatives. They generally have tails, but not grasping ones. The other line gave us the Hominoids, the apes. Gibbons, orangutans, gorillas, chimps, bonobos, and humans. A key distinction here is that apes lost their tails, and again, it’s linked to a specific shared genetic mutation, indicating it happened once in the common ancestor of all apes after they split from the Old World monkeys.

So, here’s the punchline for the classification question. Everyone agrees New World monkeys are monkeys. Everyone agrees Old World tailed monkeys are monkeys. If you want to make the smallest possible complete evolutionary group (a monophyletic clade) that contains all these agreed upon monkeys, you have to go back to the ancestor of all Simians.

But the rules of clades say you must include all descendants of that ancestor. And who are the descendants? New World monkeys, Old World monkeys, and apes. Apes (including humans) are just one branch of the Catarrhines, which is one branch of the Simians. We are nested within the group that contains all monkeys. Therefore, applying the standard biological classification rules consistently, humans are a type of monkey, specifically a type of tailless, Old World, catarrhine monkey.

Okay, so that seems to be the biological answer based on tracing descent.

Now, back to the reflection I posed earlier, why is it important that people understand this? Why push back against the common feeling that we’re somehow separate?

Well, I would say that it links back to that feeling of human specialness. In an opportunity I had, I posed some related questions to Peter Singer. One was whether the focus on ‘human rights’ might actually hinder thinking about rights for others, precisely because it reinforces this idea that being human is inherently special. His answer was basically yes, it makes us think we are very special just by belonging to our species. My second question was whether advocating for animal rights is suppressed mainly because it’s not economically profitable. He disagreed with ‘suppressed’, suggesting instead that most people simply eat meat, and this self-interest makes it hard for them to objectively consider arguments against speciesism.

Putting these ideas together with our classification, it seems relevant. If we struggle to accept being biologically classified as a type of monkey, isn’t that stemming from the same feeling of inherent specialness that Singer mentioned? A specialness that makes it convenient to overlook our biological continuity and harder to objectively consider our treatment of other species? Maybe accepting our place firmly within the animal kingdom, within the monkey group even, challenges the very basis of the human exceptionalism that allows speciesism to flourish. The human detachment from our biological reality, subtly reinforced by misclassifications or refusals to classify ourselves consistently, might indeed have actual implications.

It might even tie into how we evaluate other beings. Think about ‘intelligence’. We often use it as a yardstick to justify our perceived superiority.

An interesting research question I would one day like to pursue, by the way: how many graduate-level people actually think that chimps and other animals are on an evolutionary path ‘towards’ becoming more intelligent like humans?

Because, let me say, the answer to the underlying question seems to be no, evolution doesn’t work like that, and a being isn’t necessarily ‘on the way’ to becoming more human-like intelligent. And this is talking about ‘intelligence’ in that strict sense, that to be honest, if I were to be excessively detailed in analysis, I wouldn’t exactly know what that even means.

To clarify it, it looks like this word usually refers to human cognitive attributes. Which, on the individual level, isn’t always so impressive even when compared to some non-humans. For example, chimps have outperformed humans on certain memory games. Isn’t that memory a facet of intelligence? I find it a little less than optimally intelligent that humans often only know they are pregnant months after it happens, and usually need external technological tools to confirm it. Dolphins, I have heard, know almost from the get-go. So again, what ‘intelligence’ counts? Or are we just cherry-picking the cognitive traits that make humans look uniquely special?

This whole discussion of defining intelligence to suit ourselves feels important. It’s convenient, isn’t it? Set the rules of the game so you’re guaranteed to win, then declare yourself champion. It allows us to maintain the comforting illusion of clear superiority.

If we genuinely broadened the definition, perhaps including emotional intelligence, long-term planning capability beyond a single generation, bodily awareness, sensory acuity in different spectra, or even something like sustainable ecosystem integration, the human ranking might look rather different. Less like a clear peak, more like a creature with a very specific, very lopsided skill set. Powerful in some ways, remarkably deficient in others. Our prowess in abstract thought sits awkwardly alongside our collective inability to stop polluting the water we drink. How intelligent is that, really, in the grand scheme?

This relates back to the monkey classification business. The refusal to accept our place within that nested biological hierarchy seems tied to this same need to feel exceptional, to be defined by the traits where we excel, while conveniently ignoring the biological and cognitive continuity we share with other primates, other mammals, other life forms. If we acknowledge we are, technically speaking, a specific kind of monkey, it implicitly acknowledges shared vulnerabilities, shared ancestry, shared basic biological imperatives. It grounds us. And perhaps that grounding is precisely what feels uncomfortable to a species that has built so much of its identity, its economic systems, and its ethical justifications on the idea of being separate, above, fundamentally different.

The consequences of this cultivated detachment are all around, I think. It allows us to operate with a kind of compartmentalization. We can mourn the extinction of a species in a documentary one minute, then support economic systems that drive habitat destruction the next. We can express affection for individual animals, pets perhaps, while simultaneously participating in industrial-scale exploitation of other species deemed ‘food’ or ‘resources’. This isn’t necessarily overt hypocrisy for most; it’s the logical outcome of a worldview that places humans in a special, protected category, subject to different rules.

Accepting our place within the primate lineage, within the monkey group, doesn’t automatically fix this compartmentalization. Cognitive dissonance is a powerful human trait. But it does make the inconsistency harder to ignore. It provides a factual basis, grounded in the same scientific reasoning we use elsewhere, for challenging the notion of fundamental separation. When the foundations of exceptionalism are weakened, the structures built upon them might also become less stable. Maybe.

Let's now consider the implications for how we structure society or make policy. If human well-being is seen not as the sole objective, but as one crucial part of a larger ecological system’s health, priorities might shift. Valuing biodiversity might move from a nice-to-have peripheral concern to a central requirement for long-term human survival, recognizing our dependence. Resource management might look less like maximizing short-term extraction for human profit and more like maintaining system balance for multi-species thriving. Ethical frameworks might evolve to grant stronger consideration, perhaps even rights, to non-human entities possessing demonstrable sentience or ecological significance.

These shifts seem radical now precisely because they challenge the anthropocentric baseline. But if that baseline rests partly on a flawed perception of our own biological separateness, then correcting the perception is part of the work needed to make those radical shifts seem less radical, more logical, more necessary.

Of course, the inertia is immense. People have lives to live, bills to pay, anxieties to manage within the systems that exist now. Suggesting that rethinking our phylogenetic classification has relevance to global economics or climate policy can easily sound abstract, irrelevant, like philosophical navel gazing while the house is on fire. And maybe it is.

I any manner, my view is that accepting our place as a specific kind of primate, a specific kind of monkey, isn’t about self-flagellation. It’s about accuracy. It’s about intellectual honesty. It’s about looking at the evidence of our shared ancestry and not flinching or inventing special exceptions for ourselves.

It feels like a necessary step towards dissolving the harmful illusion of our disconnection. We are creatures of this planet, evolved alongside everything else, subject to the same fundamental biological and ecological laws. It might be that grasping our situatedness, our animal nature, our monkey kinship, helps cultivate the kind of perspective needed to wield that power more responsibly, more wisely. It’s less about what we are called, and more about understanding what that implies about our relationships and our responsibilities. It’s about seeing the world, and ourselves within it, just a little more clearly. And hoping that clarity might eventually, somehow, translate into behaving a little less destructively.