The Selfish Gene

by

Richard Dawkins

Teachers and parents! Our Teacher Edition on The Selfish Gene makes teaching easy.

The Selfish Gene: Chapter 9 Summary & Analysis

Summary
Analysis
Trivers argues that sexual relationships are shaped by mutual mistrust and mutual exploitation. Dawkins agrees, because from a genetic perspective, mates are not genetically related. Mates share an investment in their child (which has half of each parents’ genes), which demands a certain amount of cooperation, but overall it would be a smart strategy to trick the other parent into “caring” for existing children, and focus on more mating, to get more genes into the gene pool.
Dawkins is shifting from describing individuals that are genetically related (such as parents and children), to individuals that aren’t. He starts with mates which are not genetically related, but have a potential shared genetic investment in common (their children). Dawkins wants to run through some of the behaviors in the mating game to show that even here, selfish genes account for what happens.
Themes
Selfishness, Altruism, and Cooperation Theme Icon
In order to address selfishness and altruism between mates, Dawkins first needs a way of characterizing the sexes. The problem is that many species don’t have the same markers of sex as humans do. For example, male frogs don’t have penises. The only consistent difference across species is that the egg is larger than the sperm. Dawkins decides to call organisms with small sex cells “male” and organisms with large sex cells “female.” 
Dawkins wants to show that selfish genes explain all mating behavior in the natural world.  First, he needs a uniform way to address a diverse array of mating practices. The only commonality across species is that mating happens with a small sex cell (which he’ll call male) and a large sex cell (which he’ll call female). These two types of cells are distributed (and united during mating) in diverse ways depending on the species, but ultimately, mating in all species involves both. 
Themes
Selfishness, Altruism, and Cooperation Theme Icon
The first thing that’s obvious from the get-go is that larger sex cells provide more nourishment for the embryo. Even at this stage, the female contributes more. Dawkins says that “female exploitation begins here.” It’s likely that natural selection favored large female sex cells, since more nourishment gives the embryo a good start. If so, it would have made good sense for the male sex cells to evolve to be as small as possible (effectively making more small sex cells than few big ones). In this sense, eggs are playing an “honest” behavior strategy and sperm are “exploiters.”
Dawkins thinks the size discrepancy between large (female) sex cells and small (male) sex cells explains why “female exploitation” happens: even from the start, the female cell has already invested more in the potential offspring. Genes that create small sex cells effectively “cheat.” Interactions between individuals often involve honest and cheating strategies. Dawkins will explain these at length to debunk the group selection idea that some organisms are inherently “honest” (altruistic) and others are inherently “exploiters” (selfish). He means that discrepancies in behavior strategies will arise, but genes will always trigger behavior that gives them the best chance of surviving, even if they start out at a disadvantage.
Themes
The Gene’s Eye View of Evolution Theme Icon
Selfishness, Altruism, and Cooperation Theme Icon
Dawkins believes that group selection theorists run into problems when sex ratios come up, since it’s obvious that only need one or two males are needed to get a whole population going. In many animal populations, only some of the males actually mate. For example, only 4 percent of male elephant seals mate. So, why don’t the other males kill themselves to save resources for the good of the species? 
Dawkins wants to show that the group selection view can’t explain why there are equal sex ratios in most (if not all) populations. If altruism did exist, it would make sense for non-mating individuals to commit suicide for the good of the species, but they don’t. So, the group selectionists must be wrong.
Themes
The Gene’s Eye View of Evolution Theme Icon
Selfishness, Altruism, and Cooperation Theme Icon
Get the entire The Selfish Gene LitChart as a printable PDF.
The Selfish Gene PDF
Dawkins believes that selfish genes provide a better explanation for why there are roughly equal numbers of males and females in a species. R. A. Fisher’s research explains sex ratios from the gene’s eye view. Suppose that among elephant seals, there’s a trait for having more daughters than sons. This would work for a while, as the group would survive even with only a few sons doing all the mating. Daughters would become very common. But then sons would have an advantage, since they’d be doing most of the mating. So, the gene for having sons would spread through the group and become numerous. Ultimately, an equal ratio of males to females ends up being the evolutionarily stable state.  
Fisher gives a gene’s eye view explanation of sex ratios, which Dawkins uses to show that the selfish gene accounts for these as well, and is thus a better account of evolution than the group selection view. When sex ratios are uneven in a population, they swing back and forth with each generation because each sex has a genetic advantage when their numbers are limited. The ratio that stays consistent over multiple generations (or, the evolutionarily stable state) is equal numbers of males and females.
Themes
The Gene’s Eye View of Evolution Theme Icon
Selfishness, Altruism, and Cooperation Theme Icon
Dawkins recalls that he is thinking of individuals as survival machines for their genes. Each individual wants to mate and pass on as many genes as possible.  It makes good sense to trick one parent into caring for existing children while the other keeps mating. Dawkins thinks it’s harder for females to trick males because their sex cells are larger, meaning they have already invested more in the embryo than males. Females have more to lose if the offspring doesn’t survive, especially if the female has incubated an embryo in her body. This means that males face more evolutionary pressure to desert their mates. 
Dawkins decides to address situations in which parents abandon their young. According to the gene’s eye view of evolution, males have less to lose from shirking the responsibility of childcare, since smaller sex cells mean a smaller energy investment per child. Yet in nature, many different childcare practices exist. Dawkins runs through a few of these to show that neither group selection nor altruism play a role in these dynamics. Rather, they exist because successful selfish genes are able to program their survival machines with strategic traits that even the balance.
Themes
The Gene’s Eye View of Evolution Theme Icon
Selfishness, Altruism, and Cooperation Theme Icon
What about a deserted female, however? Trivers thinks it would make sense for her to trick another male into thinking the baby is his. He thinks this is why male mice evolved to secrete chemicals that trigger a miscarriage when inhaled by a female carrying another mouse’s embryo. Similar counter-strategies include male lions murdering existing cubs when joining a pride, and males who prefer long courtships before mating, just in case the female is already pregnant.
Consider male mice who secrete chemicals that kill other mice’s embryos in their female mates. Clearly, this makes no sense from the group selection view, since the behavior seems to inhibit (rather than help) the success of the group overall. It makes perfect sense from the gene’s perspective however, since the male mouse’s genes are the only things to benefit from this behavioral trait.  
Themes
The Gene’s Eye View of Evolution Theme Icon
Trivers also believes that female birds require extensive courting because it makes males less likely to desert them after mating. The male has to secure territory and build a nest. With an increased investment in the courtship, he has more to lose by walking away. Dawkins disagrees, because he doesn’t think prior investment makes males more likely to invest more in the future, especially if there are other females in the group who demand less of their mates.  
Trivers argues that courtship rituals involving a lot of labor for men benefit aren’t altruistic. Rather, females only mate with males who have increased their labor before mating to even out the balance of the female’s extra investment in childbearing. Dawkins disagrees, but once again indicates that other scientists support the idea of denying altruism, even if they don’t agree on specific details.
Themes
Selfishness, Altruism, and Cooperation Theme Icon
Dawkins draws on Maynard Smith to work out the likelihood of females being “coy” (require a lot of courting) versus “fast” (easy to court), and males being “philanderers” (likely to desert his partner) versus “faithful” (likely to stay and care for future offspring). If one does the math, looking at the genetic costs and benefits of each strategy over a few generations, it turns out that the evolutionarily stable state is reached when most females act “coy,” and just over half the males act “faithful,” or when females act coy most of the time, and males act faithful more often than not.
Dawkins uses Maynard Smith’s mathematical calculations to address flirting and cheating in nature. He doesn’t think it’s because some individuals are inherently more altruistic than others. The actual balance of flirty (“fast”) females, aloof (“coy”) females, “faithful” males, and cheating males (“philanderers”) exists because that balance becomes evolutionarily stable. The ratio that exists in nature enables all of those genes to survive for generations to come, in the exact same proportions. 
Themes
Selfishness, Altruism, and Cooperation Theme Icon
Dawkins speculates that it pays off for females to be coy in ways that enhance egg cultivation. He thinks this is why “courtship feeding” happens. In many bird species, the male has to feed the female for a length of time before mating, which gives her (and her sex cells) energy for future embryos. Courtship feeding happens among insects and spiders too. For example, it’s smart for a praying mantis to feed his mate before copulating, because it reduces the chance of her being hungry and eating him after mating.
Dawkins argues that even courtship feeding, in which males feed females prior to mating, is not altruistic. In birds, the female’s selfish genes benefit from mating with males who feed them, since it makes their embryos more likely to be well-nourished and survive to reproduce. In praying mantises, the male’s genes benefit from feeding his mate so that she doesn’t eat him when mating. 
Themes
Selfishness, Altruism, and Cooperation Theme Icon
Dawkins wonders why there are some species in which males look after embryos or children. This happens a lot in fish.  He concludes that since fish spray their sex cells into the water (where they combine), and embryos aren’t grown in the female’s body, it pays for the female to spray her cells near a male and then desert him.
Another possible case of altruism in nature arises when males look after embryos or children, which is common among fish. Dawkins argues that male fish don’t take on that responsibility to be nice. Rather, the mating procedures give females an advantage in shifting the burden of childbearing. Once again, selfishness (and not altruism) explains this tendency among fish. 
Themes
Selfishness, Altruism, and Cooperation Theme Icon
Many people think females are drawn to mates for reasons like having long legs to escape predators, or strong arms to carry food. Darwin thought this was incorrect, and Dawkins thinks so, too. He thinks females want sons who are likely to breed and pass on their genes. This means older mates are better (because it’s clear they live long and can breed more), and attractive mates are best (since inherited attractiveness will help their own sons mate later on).  
Scientists often disagree on what motivates sexual attraction. Dawkins thinks the answer is very simple: being good looking increases one’s chance of mating and passing on one’s genes. This seemingly superficial explanation once again puts a selfish gene at the center of the explanation: the gene for attractiveness.
Themes
Selfishness, Altruism, and Cooperation Theme Icon
Zahavi has another explanation. He thinks that some males have “handicaps” (like large antlers, or long flowing tails) to show females they are strong and powerful despite these handicaps, meaning they’re more attractive overall. Dawkins finds Zahavi’s explanation a bit ridiculous. Dawkins thinks it’s clear that strong males mate with females because they win fights with challengers who try to move in on their “harems.” Dawkins believes he’s shown that selfish genetic motivations underlie a host of mating behaviors, including monogamy, promiscuity, and harems. He wants to show that this is true for other aspects of mating too.
Dawkins discusses some of Zahavi’s alternative genetic explanations for attractiveness, which he disagrees with. This disagreement implicitly invites the reader to think about explanations they might provide themselves, which draws them further into engaging with the gene’s eye view of evolution. Meanwhile Dawkins moves on to address even more behaviors in the mating game, to show that gene survival is behind all of them.
Themes
The Gene’s Eye View of Evolution Theme Icon
Birds with brightly colored feathers attract mates, but birds with “drab” feathers blend in and hide from predators. Dawkins thinks that both kinds of genes compete, and what actually happens is a compromise. Females have “drab” feathers and males have colored feathers. Eggs are a scarcer resource, so females don’t need bright colors to nab a mate, but muted feathers help disguise them from predators. Males, however, only need to live long enough to mate to keep their colored feathers in the gene pool, even if they are eaten by predators shortly after. Females who are “fussier” about choosing a mate have a smaller chance of accidentally breeding with the wrong species (for example, with a donkey instead of a horse) and birthing sterile offspring, which stops their genes from living on in the gene pool.
Dawkins explains that eggs are rarer than cells, meaning that generally, males compete for female mates, and not vice versa. In males, the genetic benefit of blending in with one’s surroundings to hide from predators is outweighed by the benefit of standing out to attract a mate. Similarly, among females, the genetic benefit of being pickier about mates is higher than mating more freely. In each case, the behavior persists because it’s the strategy that keeps the most genes alive. Dawkins believes his thorough examination of mating behaviors shows that the strongest and most consistent explanation for why they happen is selfish genes.
Themes
The Gene’s Eye View of Evolution Theme Icon
Selfishness, Altruism, and Cooperation Theme Icon
However, the oddest mating habits in a species actually arise in humans. Human women tend to beautify themselves and act as if they are competing for male mates. This is the opposite of what normally happens in nature.  
The biggest anomaly, it seems, occurs in humans, in which women compete for male mates. Dawkins is implying that something other than biology explains this tendency. Later, he will argue that culture accounts for many human behaviors, especially when they don’t line up with what goes on in nature.
Themes
Culture and Memes Theme Icon