Inter-Species Competition

A gazelle on the African savanna is trying not to be eaten by cheetahs, but it is also trying to outrun other gazelles when a cheetah attacks. What matters to the gazelle is being faster than other gazelles, not being faster than cheetahs. (There is an old story of a philosopher who runs when a bear charges him and his friend. "It's no good, you'll never outrun a bear," says the logical friend. "I don't have to." replies the philosopher. "I only have to outrun you.") In the same way, psychologists sometimes wonder why people are endowed with the ability to learn the part of Hamlet or understand calculus when neither skill was of much use to mankind in the primitive conditions where his intellect was shaped. Einstein would probably have been as hopeless as anybody in working out how to catch a woolly rhinoceros. Nicholas Humphrey, a Cambridge psychologist, was the first to see clearly the solution to this puzzle. We use our intellects not to solve practical problems but to outwit each other. Deceiving people, detecting deceit, understanding people's motives, manipulating people—these are what the intellect is used for. So what matters is not how clever and crafty you are but how much more clever and craftier you are than other people. The value of intellect is infinite. Selection within the species is always going to be more important than selection between the species.

Now this may seem a false dichotomy. After all, the best thing an individual animal can do for its species is to survive and breed. Often, however, the two imperatives will be in conflict. Suppose the individual is a tigress whose territory has recently been invaded by another tigress. Does she welcome the intruder and discuss how best they can cohabit the territory, sharing prey? No, she fights her to the death, which from the point of view of the species is unhelpful. Or suppose the individual is an eaglet of a rare species anxiously watched by conservationists in its nest. Eaglets often kill their younger brothers and sisters in the nest. Good for the individual, bad for the species.

Throughout the world of animals, individuals are fighting individuals, whether of the same species or of another. And indeed. the closest competitor a creature is ever likely to meet is a member of its own species. Natural selection is not going to pick genes that help gazelles survive as a species but hurt the chances of individuals—because such genes will be wiped out long before they can show their benefits. Species are not fighting species as nations battle other nations.

Members of a species compete with one another as well as with other species.