Survival of the sneakiest

‘The race is not to the swift,” we learn from scriptures, “nor the battle to the strong.” But as Damon Runyan once wrote, that’s the way to bet. One of my students at the University of Washington, where I taught animal behaviour and evolutionary biology, once asked me if the Bible was inconsistent with evolution by natural selection, since — as she understood it — the biological race is indeed won by the swift and battles by the strong. She was surprised by my response.

I grant that much of the time, Runyon’s cynicism is consistent with the non-human world, no less than the human one. When a cheetah chases a gazelle, the race is typically won by whichever is swiftest. This arms race between predator and prey has resulted in remarkable speediness on the part of each: Faster gazelles select genetically for faster cheetahs, and vice versa.

But as I explained to my student, even in the supposed world of “nature red in tooth and claw”, the fiercest don’t always win. This is especially true because “winning” in evolutionary terms has very little to do with being victorious mano a mano (hand to hand), and everything to do with being successful in getting one’s genes projected into the future. (More precisely, winning genes are those that manage to promote identical copies of themselves in succeeding generations.)

Examples are legion. Among those highly aggressive bull elk, some individuals spend so much time and energy displaying and fighting that unassuming and unaggressive bulls sometimes sneak into the harem while the ostensible lord and master is preoccupied with maintaining his dominion by clashing antlers with his more obvious competitors.

Ornithologists have even coined the phrase “aggressive neglect”, referring to the observation that some male birds are so busy defending their territories against interlopers that they neglect their paternal duties to provision their young, who end up undernourished and sometimes dead. Not a good evolutionary outcome for the pushy, ostensible “winners”.

The biological world also offers a panoply of cases in which a seemingly winning tactic — often involving high levels of aggression — is paradoxically undone by its own success, resulting in a balance between the assertive and the downright meek.

Among pumpkinseed sunfish, for example, some males are relatively large and heavily pigmented; they vigorously and conspicuously defend territories in which they mate with females. One might think that selection would strongly reward effective territorial defence, so that males would be as large and imposing as their ecological niche permits.

But when the sunfish population consists of mostly strong, aggressive, highly pigmented and assertive males, the opportunity arises for males of a very different sort to enter the picture. These individuals — though fully male, in that they produce sperm — are female mimics. The territorial males welcome them into their aquatic boudoirs, whereupon immediately after a real female deposits her eggs, the female mimics release their sperm, and then skedaddle.

The traditional large males are readily fooled so long as the mimics are rare, but as more mimics succeed, the big fish become less abundant and the mimics more plentiful. Then the dynamic turns. Those traditional males become increasingly aware of the presence of mimics and keep them away, whereupon the number of those assertive males rises once again. At equilibrium, the evolutionary race is not only to the big and aggressive, but also to a certain number of the small and sneaky.

I never advised my students to take their cues from natural selection. Evolution is a wonderful thing to learn about, but a terrible thing to learn from. By the same token, although I strongly recommend learning about the scripture — after all, familiarity with it is a prerequisite for basic cultural literacy — I also wouldn’t recommend deriving all of one’s ethical precepts from it. But even though it isn’t clear that the meek (whether animals or people) will inherit the earth, it is worth noting that our modern understanding of animal behaviour and evolution is at least compatible with the other side of scripture: Urging the legitimacy of a kinder, gentler perspective on how best to live.

David P. Barash is Professor of Psychology emeritus at the University of Washington. He has written, edited or co-authored more than 40 books.