The Sports Gene: Inside the Science of Extraordinary Athletic Performance by David Epstein
Authors: David Epstein
Tags: Non-Fiction
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Because of a long gestation and breastfeeding period, a female gorilla can produce only one offspring about every four years. Male gorillas collect and defend harems of females and have a much higherpotential reproductive rate. But for each male gorilla that has a harem, several other males are frozen out of breeding altogether. The result is that male gorillas compete fiercely for access to multiple females, and this “male-male competition” takes the form of fighting, or at least posturing to fight, and natural selection accentuates traits that make gorillas better fighters. “In species where females have a higher potential reproductive rate,” like seahorses, Geary explains, “the situation is reversed, and the females are bigger and more aggressive.” Not surprisingly, male seahorses, which care for eggs, prefer larger, stronger females.
In competition zones that are more difficult to patrol and defend physically—the sky, for example—the female’s choice of a mate becomes more significant and natural selection accentuates male traits such as the attractive coloration and melodic courtship songs that occur in birds. But in primates that are confined primarily to terra firma, like gorillas and ancestral humans, head-to-head fighting can be important and evolution accentuates brute strength.
All this implies some less-than-happy notions about humans, the earth-bound primates that we are, and men in particular: that certain traits were selected for in men so that they could hurt, kill, or at least intimidate one another, and that the men who were most successful at hurting, killing, or intimidating other men sometimes used that success to mate with multiple women and to have lots of children.
The weight of evidence supports both implications. Across hunter-gatherer societies, around 30 percent of men died at the hands of other men, in combat or in raids, which often were carried out in order to capture women. As Harvard psychologist Steven Pinker put it in a talk about his book
The Better Angels of Our Nature
, about the history and modern decline of human violence: “It turns out that [Thomas] Hobbes was right. Man’s life in the state of nature was nasty, brutish, and short.”
The second implication, that our ancestral man strove for multiple mates, is indisputable from the genetic evidence. Because fathers passtheir Y-chromosomal DNA only to sons, and only mothers pass on a type of DNA called mitochondrial DNA, we can trace our maternal and paternal ancestors separately back through time. The findings in studies throughout the world are clear: no matter where scientists look, we have fewer male than female ancestors. It took far fewer Adams than Eves to spawn the world’s current population. (In some cases staggeringly so: 16 million Asian men—0.5 percent of the world’s male population—have a nearly identical portion of the Y chromosome that geneticists think probably came from Genghis Khan, who famously had hundreds of wives and concubines.)
Another pattern that holds across species and among primates that have intense male-male competition is that the physical abilities important to combat are bolstered, exclusively in males, via puberty. Puberty accentuates the qualities that a burgeoning adult is soon to need for reproduction. So if athletic traits, like throwing punches or rocks, are important to reproduction, they will be magnified during puberty. And here again, men follow the violent primate pattern to a tee. Whereas girls mature early and quickly, boys go through a puberty that is both late and long, giving more time for growth, and during which their athleticism explodes.
Up until the age of ten, girls and boys have similar bodies. Girls are taller and already have slightly more body fat, but a number of athletic traits are nearly indistinguishable in boys and girls. Top running speed is almost identical in ten-year-old boys and girls, and close all the way until age fourteen,
Because of a long gestation and breastfeeding period, a female gorilla can produce only one offspring about every four years. Male gorillas collect and defend harems of females and have a much higherpotential reproductive rate. But for each male gorilla that has a harem, several other males are frozen out of breeding altogether. The result is that male gorillas compete fiercely for access to multiple females, and this “male-male competition” takes the form of fighting, or at least posturing to fight, and natural selection accentuates traits that make gorillas better fighters. “In species where females have a higher potential reproductive rate,” like seahorses, Geary explains, “the situation is reversed, and the females are bigger and more aggressive.” Not surprisingly, male seahorses, which care for eggs, prefer larger, stronger females.
In competition zones that are more difficult to patrol and defend physically—the sky, for example—the female’s choice of a mate becomes more significant and natural selection accentuates male traits such as the attractive coloration and melodic courtship songs that occur in birds. But in primates that are confined primarily to terra firma, like gorillas and ancestral humans, head-to-head fighting can be important and evolution accentuates brute strength.
All this implies some less-than-happy notions about humans, the earth-bound primates that we are, and men in particular: that certain traits were selected for in men so that they could hurt, kill, or at least intimidate one another, and that the men who were most successful at hurting, killing, or intimidating other men sometimes used that success to mate with multiple women and to have lots of children.
The weight of evidence supports both implications. Across hunter-gatherer societies, around 30 percent of men died at the hands of other men, in combat or in raids, which often were carried out in order to capture women. As Harvard psychologist Steven Pinker put it in a talk about his book
The Better Angels of Our Nature
, about the history and modern decline of human violence: “It turns out that [Thomas] Hobbes was right. Man’s life in the state of nature was nasty, brutish, and short.”
The second implication, that our ancestral man strove for multiple mates, is indisputable from the genetic evidence. Because fathers passtheir Y-chromosomal DNA only to sons, and only mothers pass on a type of DNA called mitochondrial DNA, we can trace our maternal and paternal ancestors separately back through time. The findings in studies throughout the world are clear: no matter where scientists look, we have fewer male than female ancestors. It took far fewer Adams than Eves to spawn the world’s current population. (In some cases staggeringly so: 16 million Asian men—0.5 percent of the world’s male population—have a nearly identical portion of the Y chromosome that geneticists think probably came from Genghis Khan, who famously had hundreds of wives and concubines.)
Another pattern that holds across species and among primates that have intense male-male competition is that the physical abilities important to combat are bolstered, exclusively in males, via puberty. Puberty accentuates the qualities that a burgeoning adult is soon to need for reproduction. So if athletic traits, like throwing punches or rocks, are important to reproduction, they will be magnified during puberty. And here again, men follow the violent primate pattern to a tee. Whereas girls mature early and quickly, boys go through a puberty that is both late and long, giving more time for growth, and during which their athleticism explodes.
Up until the age of ten, girls and boys have similar bodies. Girls are taller and already have slightly more body fat, but a number of athletic traits are nearly indistinguishable in boys and girls. Top running speed is almost identical in ten-year-old boys and girls, and close all the way until age fourteen,
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