Caturday felid: a rationalist cat writes in about human evolution

As I’ve mentioned before, I am friends with Malgorzata Koraszewska and Andrzej Koraszewski, who run the highly popular Polish website Racjonalista, which has thousands of secular followers starved for a non-theist viewpoint in an overwhelmingly Catholic country.

Malgorzata translates many of this website’s articles into Polish, and so we have struck a deal: in return for the right to translate any of my pieces without asking, I get a daily “Hili Dialogue.” Hili is their young tabby cat, and every day Andrzej has a two-line dialogue with her, with Hili showing her characteristic haughtiness, inquisitiveness, and, above all, penchant for noms.  The dialogue always includes an appropriate photo.

I thought I’d put up today’s Hili Dialogue since it’s one of the rare ones that mentions me.

Hili: I must ask Jerry, when people lost possibility to care for their hygiene without all those artificial tools.

Andrzej: Get thee to a nunnery, and let me clean my teeth.

(Note that Hili’s back paw is green. She recently injured it, and the color is from an antibiotic ointment.)


Since this is a question about human cultural evolution, I thought I’d answer it for Hili.

Dear Hili,

I could construe your question in either of two ways: when did humans first start using tools? Or when did humans first start using toothbrushes?

The first question is much easier to answer, since tools and their markings are preserved much more readily than are toothbrushes.  There is questionable evidence of human tool use about 3.4 million years ago, about 2-3 million years after our ancestors had split from those of modern chimpanzees.  This “evidence” consists of cut marks on and crushed segments of animal bones, and those bones are associated with the remains of Australopithecus afarensis in an Ethiopian site dated 3.4 mya.  The authors of that study, published in Nature in 2010, suggested that the cut marks and crushed regions reflect the use of stone tools for butchering.

That work got a lot of attention because it pushed the earliest hominin tool use back 800,000 years, since, before that, the earliest unequivocal evidence for human use of tools was 2.6 million years ago. But other workers have suggested that that early evidence for tool use might be bogus, reflecting only the trampling of those 3.4-my-old bones by other animals (they supported this by looking at marks on bones trampled by modern animals). Kate Wong at Scientific American reports on the controversy.

As I mentioned, my dear cat, the earliest widely accepted use of human tools was 2.6 million years ago. As the Smithsonian notes:

The oldest stone tools, known as the Oldowan toolkit, consist of at least:
• hammerstones that show battering on their surfaces;
• stone cores that show a series of flake scars along one or more edges; and
• sharp stone flakes that were struck from the cores and offer useful cutting edges, along with lots of debris from the process of percussion flaking.

It’s not clear which of our ancestors (or relatives) used the Oldowan tools; suggestions have involved species of both Australopithecus or Homo (e.g., H. ergaster, H. habilis). They were first described in Tanzania but have been found in many other parts of Africa as well.

Here are some Oldowan tools from the anthropology collection of the University of California at Berkeley; you can order casts of them from this site (photos by Peter Bostrom):

Chopper cores (used for crushing or as a source of stone flakes for cutting):


Flake tools:


As you know, Hili, other animals besides humans use tools: these include crows, dolphins, elephants, and octopuses. But of course domestic cats like yourself are far too clever to have to fashion tools, for you simply get humans to do your tool-using for you.  They can, for example, use can openers to release the contents of your beloved Whiskas—something that no nonhuman animal can do.

As for toothbrushes, that’s a harder question. As an article in HuffPo reveals, the earliest toothbrushes were probably just human fingers, a “tool” that would have left no trace. Apparently the Egyptians were using toothpowder made from ash, pumice, and eggshell about 7000 years ago, a concoction that would have been hard on the enamel! The ancient Babylonians cleaned their choppers with chewed-up twigs about 3500 B.C—something that I’ve also seen in modern India.

The advent of the real “toothbrush” appears to have been around 1700, with mass manufacture taking place less than a century later.  These early toothbrushes used animal hair (not cat, I hope!); nylon bristles weren’t used until 1937.

I hope, Hili, that this satisfies your curiosity. And I hope you are keeping your teeth clean!

Professor Ceiling Cat


  1. Posted July 20, 2013 at 6:51 am | Permalink

    Good timing — I’ve (finally!) just started the process of brushing Baihu’s teeth. Only a few days in, I’m still just sticking my fingers in his mouth for a few seconds at a time, slightly longer each day. When I can work my fingers all the way ’round without him being annoyed, I’ll start adding the cat toothpaste. (Don’t use human toothpaste!)


  2. ridelo
    Posted July 20, 2013 at 7:02 am | Permalink

    Hili could be a twin of my cat. Gray stripes, white paws and throat.
    Guess its a standard model.

    • Posted July 20, 2013 at 7:13 am | Permalink

      I know there’ve been posts here before on cat coat patterns. The short answer is that all the standard colors / patterns also come in an “and white” version. Black and white, orange and white, tabby and white, and so on. And it’s the back and legs that retains the patterning and the belly and paws that get the white.

      It can make for some very dramatic coats, such as in the case of Hili’s.


  3. Matt G
    Posted July 20, 2013 at 7:09 am | Permalink

    Let’s make sure we distinguish between tool use and tool manufacture. There is a great video out on the interwebs showing a corvid making a tool to fish a bucket of noms out of a deep plastic cylinder.

  4. Posted July 20, 2013 at 7:28 am | Permalink

    But chimps use tools, so I would infer that the Homo-Pan common ancestor did too. That puts earliest tool use several million years further back in time.

    • Posted July 20, 2013 at 7:39 am | Permalink

      Not necessarily. After all, we share a common ancestor with corvids and they also use and even make tools. Yet I think it safe to suggest tool use didn’t originate in our common ~300MYA ancestor.

      It seems entirely possible that our common ancestor wasn’t a tool user but had enough of the foundations laid that we both developed tool use.

      Consider that the other two great apes have very similar morphologies and yet their tool use is much less sophisticated — at least, as I understand it. It’s not at all hard to imagine a great ape that doesn’t use tools, and our common ancestor with chimps could very reasonably fit that description.


  5. Kevin Alexander
    Posted July 20, 2013 at 7:40 am | Permalink

    Boar bristles definitely. Cat hair is too soft for a cleaning brush.
    Unless you use the spines they have on their..uh, whatever.

  6. Dermot C
    Posted July 20, 2013 at 7:41 am | Permalink

    Does any other animal cook? Is there a known link between the four elements, earth, air, fire and water and the fact that they are our four ways of cooking?

    • Gregory Kusnick
      Posted July 20, 2013 at 10:01 am | Permalink

      “Four ways of cooking”? I know more than four ways, and I don’t see any obvious one-to-one correspondence between them and mystical elements. Fire in particular would seem to be a requirement for all forms of cooking.

      Where does this “four ways” idea come from? No offense, but it sounds like a deepity.

      • Dermot C
        Posted July 20, 2013 at 11:23 am | Permalink

        Four ways of cooking: baking – earth, fermentation – air, grilling – fire, boiling – water.

        Seems to me like a reasonable punt to seek a link between cooking and the ancient elements . If there’s any evidence for it, I’d be interested to know.

        • Gregory Kusnick
          Posted July 20, 2013 at 11:54 am | Permalink

          Still seems like a stretch. Baking and boiling both require fire. Fermentation happens in solution (water) and is not actually cooking at all.

          And what about roasting (fire), steaming (fire and water), frying (fire and oil), smoking (fire and air), and any number of other cooking techniques? Which ancient element animates my espresso maker or my microwave oven?

          Sorry, but I don’t see any real substance to this idea. At best it’s a metaphor, and not a very good one.

          • Dermot C
            Posted July 20, 2013 at 1:24 pm | Permalink

            Yeah Gregory, all I’m doing is speculating on how the ancient cooks might have made a link between cooking and the 4 elements.

            All of your examples include those 4 elements. Oil, assuming the ancients fried, is the spanner in the works which undermines my hypothesis. I suspect Occam might have some expertise. I’m no expert, but it’s amusing to speculate, and of course, you’re right, it’s a stretch.

            Maybe the thought process went something like this: the magical transformative process of cooking, aren’t we so much cleverer than the animals in improving on nature, aren’t these 4 elements fundamental to our superiority?

            Btw, you don’t need fire to bake: Pacific islanders bake fish in the ground, and no doubt it’s fairly common across the world

            • Gregory Kusnick
              Posted July 20, 2013 at 2:15 pm | Permalink

              What makes you think ancient cooks thought in terms of four elements at all? The idea of four (or five) elements seems to date back a few thousand years, and even then there’s some disagreement on what they are.

              Whereas cooking goes back something like a quarter million years (maybe much longer) and probably predates the evolution of language and abstract thought as we know it.

              So asking what’s the link between cooking and the four elements seems a bit like asking about the significance of Christian apologetics in knapping flint. Maybe somebody could find some way to draw a parallel, but that doesn’t mean we should take it seriously.

              • Dermot C
                Posted July 20, 2013 at 4:06 pm | Permalink


                I mean by ‘ancient’ the period before the Axial Age, in contrast with the ensuing Classical period; I don’t mean prehistory.

                In principle you could find proof for the idea in an ancient document; that the notion of the 4 elements was inspired by observation of the process of cooking. But it probably won’t happen.

                I don’t see a parallel between your analogy of apologetics and my attempt to imagine the thought processes involved in fetishizing the 4 elements. The former is dualistic and atavistic, the latter materialistic and reflective of the world as my hypothetical thinker saw it.


              • Gregory Kusnick
                Posted July 20, 2013 at 6:02 pm | Permalink

                I thought you were claiming the reverse: that techniques of cooking were inspired by the four elements. Hence my incredulity. Sorry for not catching on sooner.

                That said, I thought it was well accepted that the notion of the four elements was inspired by the observation that the world is made up of solids, liquids, gases, and energy.

  7. Diana MacPherson
    Posted July 20, 2013 at 7:49 am | Permalink

    I thought Hili’s coloured foot was from an unfortunate encounter with toothpaste!

    I’m glad Hili asked these questions as it caused me to spend all morning reading about H. ergaster.

    I’m also glad to learn of several early tooth brushing options. This gives me choices if society collapses like in The Road so I’ll have healthy post apocalyptic chompers! 🙂

  8. gravityfly
    Posted July 20, 2013 at 7:54 am | Permalink

    Hili is quite the inquisitive cat, isn’t he? Nice post, thanks.

  9. thomcan
    Posted July 20, 2013 at 9:05 am | Permalink

    Thanks for that link to the replicas of Oldowan tools. I was fortunate to visit there two years ago. That visit kick started my interest in evolution, which I did not understand to any depth. And,of course WEIT was a real help in that process. Copies of tools found there will be a great reminder.

    • Larry Gay
      Posted July 20, 2013 at 12:28 pm | Permalink

      This is exactly the kind of story I like to read.

  10. Sagra
    Posted July 20, 2013 at 9:35 am | Permalink

    My Dad used to take me for rambles in our woods and he’d show me how to make a toothbrush out of a twig from a particular tree. Sorry I don’t remember the species. He’d pull off a green twig and then chew the part that connected to the larger branch until the fibers separated into a soft brush. Viola, a toothbrush!

    In case you think he was deranged: and

    • Sagra
      Posted July 20, 2013 at 9:50 am | Permalink

      This excerpt from Carl Sagan and Ann Druyan’s Shadows of Forgotten Ancestors has chimpanzees using twig toothbrushes too.

      Stone tools get all the glory, but it’s so much easier to make a toothbrush, digging stick or a basket from plant materials. If they didn’t degrade so easily we’d probably call early humans “stick age” rather than “stone age”.

      • Larry Gay
        Posted July 20, 2013 at 12:30 pm | Permalink

        Soft twigs are great for the front surfaces. Not so good in back.

  11. Garnetstar
    Posted July 20, 2013 at 11:12 am | Permalink

    Elizabeth I in the 16th century used a tooth-cleaning cloth, a rough-surfaced fabric that was rubbed over the teeth. I don’t know if they ever thought to add an abrasive paste.

    It doesn’t seem to have been all that effective, as she had lost most of her teeth by her sixties. But then, people did that right up into the late twentieth century, almost everyone had dentures later in life.

    It seems to have been the wide acceptance of flossing that solved that problem. Any animals that are known to floss?

    • Gregory Kusnick
      Posted July 20, 2013 at 11:28 am | Permalink

      I suspect fluoride had something to do with it as well.

  12. Posted July 20, 2013 at 12:17 pm | Permalink

    Maybe this is the kind of thing Andrew Brown was referring to with “mansplaining” — man explains things to a cat.

  13. madscientist
    Posted July 20, 2013 at 4:19 pm | Permalink

    Animal hair? Probably horse tails. In some parts of Asia folks use coconut coir and coarse salt; who knows how long those practices had gone on.

  14. Dermot C
    Posted July 21, 2013 at 3:10 am | Permalink

    @Gregory Kusnick,
    Posted July 20th, 6.02 p.m.


    Apology accepted and misunderstanding noted, probably a result of my first and too runic post.

    A while back I commented about the ancient Jewish belief that the soul hovered above the corpse for three days after death. Ben Goren linked that to other ancient observations; that at the winter solstice the sun appeared to remain motionless above the horizon for three days (I paraphrase from memory, apologies if I have it slightly wrong). You can see the link to the later Classical-Age Christian allegation of Jesus’ 3 days in Sheol after death. The development over a long time period of the solstice/soul link is unproveable, tenuous, metaphorical, mystical but possible. I can imagine the solstice observation being a very early forgotten ancestor of the hovering soul idea.

    In the same way, I could posit reflections on cooking and its centrality to our survival as a very early stage in the development of the idea of the 4 elements. By the time of the Axial Age it’s imaginable that cooking was likewise the forgotten early ancestor of the 4 elements idea. That’s what I was getting at.

    And I still don’t know if other animals cook! Squirrels bake nuts!

  15. Dave Ricks
    Posted July 21, 2013 at 8:40 pm | Permalink

    The first advertisement for toothpaste –

    Ash, pumice, and eggshell –
    IX out of X dentists agree.

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