Anthropology / Everything Human

The Man Who Was Mistaken for a Homo sapiens in a Hat

Animalia

The Man Who Was Mistaken for a Homo sapiens in a Hat

human hybridization - In 1939, anthropologist Carleton Coon used an artist’s reconstruction of a Neanderthal, La Chapelle aux Saints, in a hat to show that people’s impressions of differences between groups of humans depend in part on superficial features such as clothing and facial hair.

In 1939, anthropologist Carleton Coon used an artist’s reconstruction of the Neanderthal specimen La Chapelle aux Saints in a hat to argue that people’s impressions of differences between groups of humans depend in part on superficial features such as clothing and facial hair. J. Howard MacGregor

In the winter 1957 issue of the Quarterly Review of Biology, William Strauss and A.J.E. Cave wrote of the Neanderthal, “If he could be reincarnated and placed in a New York subway—provided that he were bathed, shaved, and dressed in modern clothing—it is doubtful whether he would attract any more attention than some of its other denizens.”

The “Neanderthal in a hat” image is a bit of a cliché in the field of biological anthropology; it is associated with the idea that Neanderthals were not so brutish as originally thought and that if one were to don a fedora in the local pub, he would be mistaken for a Homo sapiens. This makes one wonder whether interbreeding between Neanderthals and Homo sapiens 100,000 years ago, as evidenced by morphology and genetics, was a result of mistaken identities or intentional digressions from traditional mate choices. If intentional, one might then ask, how common is it for individuals to recognize a member of a different species (a heterospecific) as a potentially compatible, or even high-quality, mate?

I recently came across a fascinating photo of two monkeys engaging in a mating behavior—a red colobus male was mounting a red-tailed guenon female. The photo was taken by Allegra Depasquale, an undergraduate studying red-tailed monkeys in Uganda. Neither she nor her field assistants had previously witnessed this kind of interaction between these species. After seeing the photo, I started thinking more intently about this question of mate recognition in the context of my previous post about hybrids and species concepts. I wondered not just about the frequency of the behavior, but also about the costs and benefits of interbreeding when there is a potential for hybrid offspring to be born.

human hybridization - Researchers in Uganda observed this very unusual mating behavior—a male red colobus monkey mounting a female red-tailed guenon.

Researchers in Uganda observed this very unusual mating behavior—a male red colobus monkey mounting a female red-tailed guenon. Allegra Depasquale

The hybrids that you are most likely to think of, like ligers and mules, are primarily the product of captivity or domestication by humans. Many of these hybrids are sterile, meaning they cannot reproduce. Frequently, this is because the parents have different numbers of chromosomes. For example, modern genetics shows that a horse has 64 chromosomes and a donkey has 62—their offspring, a mule, has 63. The difference in parental chromosome number doesn’t prevent successful reproduction in this case, but it contributes to the infertility of the offspring. (In the early 20th century, it was thought that all mules were sterile; it’s now known that a small number of female mules have produced offspring.) For this reason, mating between heterospecifics has historically been labeled as a mistake or as a failure in species recognition. But in fact there can be benefits to interbreeding—for the parents, for the offspring, or for humans.

For those of you who have your mule facts straight, you know that mules are considered to be quite smart. In fact, in a study of equine cognition, mules performed a learning task better than horses or donkeys. Mules are also known for their strength relative to their size and for their endurance. This kind of outcome is known as “hybrid vigor.” And it’s why humans love their mules. Domestic mules are just one example of the intentional crossbreeding of animals by humans—something Homo sapiens have been doing for as long as 10,000 years and for a variety of (sometimes selfish) reasons.

In the wild, at least 10 percent of all animal species are known to hybridize, and there may be benefits to interbreeding for them as well. In her article “Why Do Animals Hybridize?,” biologist Pamela Willis of the University of Texas at Austin notes that a common scenario in which hybridization naturally occurs involves secondary contact of two populations that had been separated geographically—think of the “hybrid zones” between baboon populations that I described in my earlier post. This behavior may help introduce variation into a population, which may be evolutionarily beneficial.

In the wild, at least 10 percent of all animal species are known to hybridize.

“Indiscriminate forceful or sneak copulations [by males] have been associated with hybridization in several species, including ducks, frogs, sea lions, damselflies, and, most extensively, fish,” writes Willis. These behaviors may be influenced by a shortage of conspecific (same species) mates and have the potential to boost a male’s reproductive fitness.

In addition, one or both parents may benefit from having a heterospecific mate through reduced predation risk, reduced competition for breeding habitats, or increased nutritional benefits. Mating with a heterospecific may even make an individual more attractive or noticeable to conspecifics. As Willis points out, there are many hypotheses regarding the potential reasons for and benefits of natural hybridization that can be tested.

So what motivated Neanderthals and Homo sapiens to mate? Was hybridization simply a result of secondary contact? Did they mistake each other for conspecifics or intentionally copulate? Were males being sneaky or forceful? And finally, do you think Neanderthal–Homo sapiens hybrids could have been stronger or smarter than their parents?

Evolution / / /

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  • christopher_y

    I read an SF novel whose title and author I have forgotten, which suggested that Neanderthals found AMHs irresistibly cute because neotenous. As good a theory as any?

    • Val D.

      now you must share the title!!

  • Gabrielle

    However! The action of mating between Neanderthal and Homo Sapiens was only successful if it was a WOMAN Homo Sapien! Neanderthal MEN were more than likely putting their penis in anything they could get their hands on. There are many studies on Neanderthal women pelvic bone that reveal their narrow shape while Homo Sapien women have a more bowl like shape which allows for our huge infant craniums to be able to pass through the vaginal canal. Unfortunately for the Neanderthal women their pelvises were so narrow that any Homo Sapien male offspring they carried to term would have killed both mother and child. That was the death of the Neanderthal. Homo Sapien women were raped by Neanderthal males, which allowed Neanderthal traits to exist today.

  • Kathy Dettwyler

    Or . . . . . . Neanderthals and Homo sapiens were the very same species and always have been.

    • Caitlin S

      Kathy – that is certainly an argument some researchers would make. I would refer you (if you haven’t read it) to my previous post about hybrids and species concepts and would love to hear what you think about that – are species just constructs of the human mind or are they realities of nature? How do we decide whether AMH and Neanderthals were the same or different species? Thanks for your comment!

  • Jim O’Donnell

    Caitlin, first, great blog post. It is not something I’d given much thought to. A few months back I think, a researcher from the Max Planck Inst and another researcher both presented evidence suggesting that many things like allergies and hayfever might have been passed to us by interbreeding with Neanderthals and/or a Denisovan ancestor. Just curious if you saw that and what you thought of it. Perhaps for us, unlike with mules, there was a detriment to cross-species breeding. Just curious.

    • Caitlin S

      Jim, thank you for raising this point. It’s fascinating to think about this. Of course, for it to be the case that modern humans possess “allergy genes” that made their way into the modern human genome as a result of interbreeding with Neandertals as much as 100K years ago, one would need to assume that there was not selection against maintaining these genes in the population (or, presumably, humans would not have those “Neandertal genes” today, right?). So…either taking on these genes was not detrimental to the hybrid offsprings’ reproductive success (not significantly, anyhow) or it was a trade-off that allowed for the expression of other traits that were potentially beneficial. Perhaps, though, your hypothesis is correct, and the reason modern human populations (particularly those of European descent) don’t, on average, have a greater percentage of “Neandertal DNA” today is due to hybrid “lack-of-vigor.” Food for thought!

  • Peter Ole Kvint

    1. Males mate with anything.

    2. It was not present people but a prehistoric human who mated with Neanderthals.
    3. It is common in small isolated communities to the rare male guests passed around among the women to break inbreeding.
    4. Neanderthals and our ancestors were the same animal species.

  • Jonathan Brookes

    There are a number of theories regarding Neanderthal extinction. Some of these center around the struggle between the already established Neanderthal population and the encroaching anatomically modern human (Homo sapiens or Cro-magnon) population in the Levant, and subsequently into Central and Western Europe.

    The theories contend that modern humans were better adapted, had superior hunting, intellectual, and social skills. These advantages ultimately forced the Neanderthal population into into less hospitable environs with substandard resources, then ultimately into extinction.

    This all may be true. However, I’d like to put forth a slightly different interpretation to the Neanderthal extinction. Sure, I’ll agree it was contention with the new human population. However, instead of the aforementioned characteristics, I believe that Neanderthals died off because modern humans were simply more attractive.

    Read more at https://jonathanbrookes.com/2015/10/09/the-ugly-extinction/