Anthropology / Everything Human

Monkeys All the Way Down


Monkeys All the Way Down

Everyone’s likely heard it or seen it written on a protest sign: “I didn’t evolve from a monkey.” It’s a well-worn refrain of those who resist the evolutionary perspective. The pat response we often hear is, “You’re right! We didn’t evolve from monkeys. We share ancestors with them.” However, this talking point isn’t entirely honest.


Yes, we did evolve from monkeys. Library of Congress

Yes, we share ancestors with monkeys; we share ancestors with every living thing. But, also, to be clear: We did evolve from monkeys.

It’s impossible to pinpoint with 100 percent certainty which fossil species are our direct ancestors and which are our more distant relatives. This is because the further we go back in time, the fewer the unique traits we share with members of our lineage, and there is often more than one species living at the same time that could be related to any given ancestor. Still, we can trace with a high degree of confidence humankind’s ancestry through fossils all the way back to the first fossils on record almost four billion years ago. One relatively tiny stretch of our lineage, spanning from roughly 40 to 20 million years ago, is populated entirely by animals that we call monkeys.

The fossilized bones and teeth of those ancient monkeys are similar to those of monkeys that exist today in many ways. And yet they’re also different. For example, the oldest fossil monkeys don’t have the distinctive shearing crests on their molars that arose later and are present in many living monkeys, like baboons. Monkeys walking around on Earth today have been evolving for just as long as we have—since the time when our shared fossil-monkey ancestors graced the planet.

Around 20 million years ago, many of those lineages of fossil monkeys kept evolving as “monkeys,” but the lineage that led to us shifted to a different branch on the evolutionary tree, which we have decided to call “apes.” Those fossil apes led to present-day ones including gorillas, chimpanzees, and us. Evolution is occurring constantly, generation upon generation, creating a spectrum of inherited variation over time. To investigate and understand that variation, we often divvy up the continuum into families, or branches on the tree of life. Because they are human inventions, the boundaries around the definitions of “monkey” and “ape” warrant scientific discussion. The necessary but ultimately arbitrary practice of taxonomy is why biological classification is so often debated. Take, for instance, arguments over whether new fossil finds are newly discovered species or variations on known ones, or the row over whether we should call ourselves “apes.”

Along with the other apes (which include chimpanzees, bonobos, gorillas, and orangutans), we evolved from ancient apes. Like modern-day apes and monkeys, we evolved from ancient monkeys. And like all vertebrates with four-limbs, known as tetrapods, we evolved from the same ancient fishes.

The more living relatives we include in a family, the farther back we must go to find that family’s common fossil ancestors. Those ancestors often have more traits in common with some living family members than others. The earliest primates, dating back to over 65 million years ago, resemble lemurs more than they resemble chimpanzees. But, of course, they’re neither. The earliest tetrapods resemble fishes more than they resemble salamanders, but they’re neither. So let’s stop pretending that our ancestors weren’t monkeys, fishes, and slimy single-celled critters. Tip-toeing around common ancestry with monkeys isn’t helpful. To one degree or another, existential questions about life’s ultimate origins run deeper than any raised by evolution.

And, of course, questions that are raised by evolution tend to lead to more questions. Scientific inquiry is a process, and one that is ongoing and incomplete. By definition, science involves uncertainties—questions without known answers. And so perhaps scientists, more than others, are comfortable with the undiscovered. Like when it comes to impenetrable questions about the origins of the universe, some of us can chalk it up to “turtles all the way down” (an infinite tower of stacked-up turtles), chuckle to ourselves, and be done with it. Others cannot, but it’s not because there’s anything wrong with them. The same is true when it comes to feelings about evolutionary thinking and those monkeys we have for uncles. Many people who struggle with these concepts are deeply thoughtful, and being dismissive of them is unhelpful at best.

Evolution / /

  • David Massie

    Aargh, No we fucking didn’t evolve from “Monkeys” because “Monkeys” is a paraphyletic grouping. Our ancestor was an Old World Monkey (Catarrhini). Our ancestores (the Hominoidea) split from the Catarrhini before the subsequent split that gave rise to the New World Monkeys (Platyrrhini), To be accurate we evolved from Old World Monkeys.
    If you want to write a science article get your definitions right.

    • Holly Dunsworth

      Hi Everybody, The comment above illustrates how passionate (and sometimes terrifyingly so) people can get about arbitrary categories that slice and dice a continuum of variation over time and space, and how we talk about those categories. None of that passion has any bearing on the FACTS that we evolved from things that came before us, some of which scientists call “monkeys” (and you’re welcome to too) even though they’re different from living monkeys. And as I discussed above, some of those weird (compared to living) monkeys of the past are not our ancestors. Peace, Holly “The Fish” Dunsworth
      P.S. We aim to eliminate jargon here, which is why you will never see “Catarrhini” in any of my posts.

      • TNT

        Hello Dr. Dunsworth,

        In David’s unnecessarily aggressive post, he does state something worth considering and that is that taxonomic classification does distinguish between Catarrhini and Platyrrhines. The categories refer to (similarities and) differences between phylogenetic groups that are the result of evolutionary processes.

        You answer affirmatively that humans (grouped within Catarrhini ) evolved from organisms that you colloquially list as “monkeys.” Since you do concede that these organisms did differ from present day monkeys then I find your post misleading. Rather it would be more accurate to suggest that Humans evolved from organisms that are similar in many respects to contemporary Monkeys but differ in others. These ancestral organisms are predecessors to Catarrhini (and Platyrrhines?).

        • Holly Dunsworth

          His post is not only aggressive, it’s wrong about the relative timing of divergences between those categories he mentions. I don’t believe it’s my responsibility to correct all incorrect comments on my blog. Given how the Internet works, that would be an unrealistic expectation.

          Regarding your second paragraph, I did state/explain that we evolved from things that are similar but not the same as contemporary monkeys. We have ancestors every step of the way back. They’re humans upon humans, until they’re not “humans” and they’re hominins or ape-men-and-women and then before that they’re apes upon apes, because we talk like this and we don’t always use terms like “hominoid” or “catarrhine” when we’re talking about our ancestors but even if someone does, they’re comfortable with that translating as “ape” or “monkey” to someone else. Before our ape ancestors (which are not living apes, they are ancient things that share things in common with us, chimps, bonobos, etc… though), there were monkeys in our lineage. That’s just how we talk. I did my dissertation on a fossil ape. It’s not a chimp or a bonobo or a gorilla or an orang or a siamang or a gibbon, it’s none of those things.It’s 20 million years old. But I call it an ape because I’m hypothesizing that it’s part of that lineage somehow and I trust that if I say “fossil ape,” people know I’m talking about something different from living ones. Often they don’t, however, and I try to be helpful like with this post on my blog.

          • TNT

            Thank you for taking the time to respond. Despite your explicit note regarding responsibility over comments, you do in fact take the time to dispute his point about the split between Ps and Cs. And you did this despite nobody suggested you should! That is how the internet works itself on us.

            The second paragraph only states that 1) the very ancient organisms are not the same as those identified by colloquial terms (which you concede), hence 2) to project this contemporary term backwards is misleading.

            In a sense, I am very much contesting the idea that phylogenetic classification is “arbitrary.” Taxonomic groupings should be supported with evidence that tell us something about how evolution affects organisms across time and space.

            In other words, I disagree with you that those ancient organisms are monkeys. They are organisms that predate contemporary monkeys. Monkey-like but still different.

        • Ritchie Rich

          You are smarter than you let on, brother, damn.

  • tinfoil hattie

    Thank you! I myself have always secretly thought it was cool to have “evolved from monkeys.”

  • Oleg Petruk

    By analogy with “non-avian dinosaurs” one
    could use “non-human monkeys” for others species
    and “monkeys” to include humans: we did not
    evolved any feature to exclude us from the

  • Pito Salas

    Nice article. I wish you had explained the origin of the all the way down expression a little more/clearly!