Category Archives: Science

Bill Bryson – The Body: A Guide for Occupants

A fun tour of the human body and all its combined miracles and foibles. As with A Short History of Nearly Everything, depth is sacrificed almost entirely to breadth. There is a sensationalist undertone throughout, especially in parts involving cancer, obesity, and growing resistance to antibiotics. Bryson lets his sense of humor shine quite a bit, adding some charm to what can be a dreary subject. This is good for novices or people who want a lighter touch on a complicated and intimidating subject. Experts will likely shake their head at Bryson’s frequent overhyping of scary but low-probability events and health conditions.

Rebecca Wragg Sykes – Kindred: Neanderthal Life, Love, Death and Art (London: Bloomsbury Sigma, 2020)

Each chapter begins with a vignette written in purple prose that is, at times, a little cringey. Once that awkwardness is out of the way, Sykes takes a series of excellent deep dives into different aspects of neanderthal life. Topics include neanderthals’ evolutionary path, their anatomy, tool-making, hunting techniques, social structures, diets, and more. Neanderthals were also artists, with clearly intentional ornamenting of shells showing up in sites dating as far back as 500,000 years ago–more than twice as old as our species.

The most significant difference between neanderthals and Homo sapiens is our social lives. Simply put, sapiens tend to have more complex social relations. Neanderthals, Sykes believes, lived in bands of about 25 people, compared to 50-150 people for our species during its hunter-gatherer days–and millions of people today.

Moreover, while neanderthal artifacts such as obsidian were known to travel a few hundred miles from their origin sites, Sykes believes they were carried by their original owners on their travels. They seem not to have been traders. Sapiens’ artifacts travel more widely, and are too diverse in origin for one person to have made, kept, and carried by themselves. They have to have traded for them from faraway specialists.

Neanderthals did have some division of labor, evidenced through different wear patterns on men’s and women’s teeth, which become more pronounced with age. This indicates more than women gathering while men hunted. Neanderthal women used their teeth in craft-making tasks such as threading, which created tell-tale wear patterns.

Neanderthals had the same family attachments that we have–unsurprising in a species close enough for us to interbreed with–and also had funeral ceremonies that evolved over time. Chillingly, these apparently often involved ritual cannibalism. Scientists can tell this from bone marks. The consistent tidiness of the patterns and the lack of defensive wounds suggest organized ritual, rather than murder.

An overlooked difference between our two species is in our shoulders. Homo sapiens are practically throwing specialists compared to the rest of the animal kingdom. It shows in our brain activity—being able to calculate parabolic trajectories and distances on the fly—and in our anatomy. Our shoulder joints are shaped in such a way that we can throw harder and with more accuracy than other primates.

While neanderthals were capable throwers, they didn’t have quite the same degree of adaptation for it. As a result, while many of our spears were clearly designed solely for throwing, neanderthal spears look to have been dual-use. They could be thrown, but their sturdier design was also good for stabbing and slashing. This is consistent with common injuries seen in neanderthal bones, which are consistent with close-quarters hunting of large mammals.

Perhaps most intriguingly, Sykes argues that neanderthals’ end as a distinct species had more to do with assimilation than with competition—and might have happened after the mostly Europe-based nenaderthal species migrated all the way to China.

My own theory has more to do with neanderthals’ smaller group size. As Adam Smith said, the division of labor is limited by the extent of the market. Smaller group size means a less refined division of labor, and less specialization. This was compounded by the fact that neanderthals engaged in less trade than Homo sapiens. Our larger group size, plus our tendency to trade over long distances was a double blessing for our species, and a double curse for neanderthals.

This is compatible with Sykes’ assimilation thesis–and most modern humans have 1 or 2 percent neanderthal DNA. But over the long run, my hunch is that sociability, trade, and division of labor were the engines that mostly drove that car.

Rob Dunn – Never Home Alone: From Microbes to Millipedes, Camel Crickets, and Honeybees, the Natural History of Where We Live (New York: Basic Books, 2018)

This is the kind of book that will make you see your home differently, mostly in a good way. It’s not nearly as icky and creep-crawly as the title makes it sound. Dunn delights in having found a hole in the “market” for scientific research. Most scientists go out in the field to do research, to the point that the places where we spend most of our time are among the least studied by naturalists. Dunn saw this opening and has made a fascinating career of working closer to home—though in the age of COVID-19, he likely has more company than he used to.

Dunn’s methods are also notable. He is a fan of crowdsourcing. For years, he has engaged the public to help him with sample-collecting and species identification. The amateur research he has encouraged has led to countless discoveries of new species and ecological niches. Some of the discoverers are as young as 8 years old. Backyard science turns out to be more than a fun activity. There are legitimate scientific discoveries waiting to be made by anyone with a little curiosity, not just professional scientists.

Something that is both obvious and overlooked is that our homes are full of extreme environments. And as a result, extremophiles that were once thought to be exotic are, in fact, extremely common in human environments. Our freezers are as cold as Antarctica, and some of the same, harmless microbes live in both places. Ovens regularly produce temperatures found only in ocean vents and deep beneath the earth’s crust—and host some of the same, harmless species. Our showers and water heaters mimic conditions of geothermal springs. In fact showers host some of the same, harmless, thermophilic bacteria that were once thought only to live in hot springs. Of course, Legionnaire’s disease also thrives in the same environment, but can’t withstand extremophile temperatures. So if you feel guilty about taking a hot shower or bath, don’t. They’re actually safer.

Household microbes and arthropods are nothing to be scared of. They have been in our homes for centuries—precisely as disease rates have plummeted and life expectancy and infant mortality have reached their lowest levels in human history. Just as cats kept rodents and their diseases and feces out of granaries, the spiders in your basement keep fly populations in check. If you like being around lots of flies, all you have to do is kill the spiders. As it turns out, delicate population equilibriums are constantly balancing themselves within feet of you while you sit on your couch and watch tv.

Spaces stations such as Mir and the ISS played/play host to many of the same species as our houses. Wherever we go, there they are. As humanity expands its ambitions in space, this will take on enormous importance. We cannot live without our symbiotic species. At the same time, they can’t overrun our artificial environments. Dunn shows how everyday environments turn out to be fascinating. And his lack of snobbery and emphasis on inclusion are something scientists in every field should learn from.

Frans de Waal – Are We Smart Enough to Know How Smart Animals Are? (New York: W.W. Norton, 2017).

The short answer to the title’s question is kind of, but not really. We can never truly get into even another human being’s head. It is impossible to tell is someone else sees the color red the same way you do, or feels hot and cold the same way. It is also clearly impossible to do this across species, which have different sensory thresholds–and in some cases, different senses–than we do.

But de Waal’s core argument is more about empathy and decency. You can tell a lot about a person by how they treat animals. By building up a persuasive case that animals have complex intellectual and emotional lives, de Waal gives good reasons for treating other species with respect. We are them, and they are us. Or, at least, we’re a lot closer than most people think.

Humans have three types of cone cells in our eyes to perceive colors, hence our three primary colors; birds have four. Mantis shrimp have 17. We will never see the world as they do. Cats and other nocturnal animals have more types of rod cells than humans do. These detect black-and-white and relative brightness, and are useful for low-light conditions. Insects have compound eyes, which are very different from our camera-style eyes. Butterflies can see ultraviolet light, which they use to assess potential mates. The UV-reflective scales on their wings wear away with age, so abundant UV reflections on their wings are indicators of youth and health for them, though humans will never know this.

But these differences are no reason to believe such animals lack intelligence. We do the same things ourselves, just in a different way. All animals live by the same four Fs: fighting, fleeing, feeding, and mating. We have evolved different ways of going about it, but the fundamentals are the same.

De Waal is also concerned with emotions. And yes, animals do feel many of the same emotions humans do. And again, our differences are more of degree than of kind. Animals feel pain, love, loss, hunger, and happiness. Maybe not in exactly the same way we do, but they do feel them.

Elephants and other animals mourn their dead, and even hold funeral services. Blood chemistry tests show that yes, your cat really does love you. Interactions with their owners release the exact same oxytocin “love hormone” that shows up in human blood when we interact with our loved ones.

Chimpanzees and bonobos—de Waal’s research specialty—have complicated social dynamics that require sophisticated emotional intelligence. They have similar notions of family and friendship, and they form complicated three-way alliances and rivalries that are very similar to the ones human nation-states build to maintain a balance of powers within the group–or in our case, global geopolitics. Our cousins, with whom we share a common ancestor as recently as six or seven million years ago, are different than each other, and from us. But the fundamentals are the same, and deserve more respect from humans.

Jennifer Ackerman – The Genius of Birds (New York: Penguin, 2017).

Her occasional lapses into prophecies of ecological doom take away from the seriousness of her case, but Ackerman has written a fascinating look at avian intelligence. Despite their tiny brain size, many birds are highly intelligent in a wide variety of areas. “Bird brain” should be a compliment, not an insult.

Parrots and songbirds are keen linguists and mimics. Corvids—crows and jays—have a strong social intelligence, long memories, an ability to learn on par with human 5-year-olds in some areas, and show tool use. Some birds are also able to differentiate the works of different artists–even ones within the same style, such as impressionism.

Migratory birds have mastered a variety of methods and senses to find their way. They use a combination of landmarks, the sun and stars, barometric pressure, a built in genetic clock (fly south for a certain amount of days, then stop), listening for the differences in sound reflections between ocean and land, as well as changing odors.

Even hummingbirds, for all their hyperactivity and tiny size, show a keen memory for food sources and plan their routes to save precious energy. Scientists have even observed hummingbirds return to the same feeders each year within a day or two every spring when they return north.

There is also good reason for birds packing as much intelligence into as little brain size as possible–it saves weight. To fly, birds have to be as light as possible. Their bones are hollow. Their lungs can absorb oxygen on both the inhale and exhale, making them nearly twice as efficient as ours, and much lighter. They have light keratin beaks instead of heavy bone jaws. So of course evolution figured out ways to make the best possible use of small and lightweight brains.

Ackerman’s case for bird intelligence would have been further strengthened if she had discussed Gordon Tullock’s famous article “The Coal Tit as a Careful Shopper,” in which Tullock finds that birds have an intuition of the laws of economics.

The coal tit, a small bird in Britain, likes to eat a kind of grub that lives inside pine cones. When food is abundant, the bird will get the easiest grubs, and leave the more difficult-to-reach ones alone. That way it spends less time getting the calories it needs, and can use the freed time for other uses, such as attracting mates and avoiding predators.

When food is scarce, those calories become more valuable in comparison at the margin, and the coal tit changes its behavior to match. It will spend more time on each pine cone, getting even the most difficult-to-reach grubs, because doing so is better than alternative uses of its time and energy. This small creature is able to use economic principles such as the law of demand, marginal thinking, and opportunity costs to improve its odds of survival.