Peeter Hõrak is Professor in Physiological Ecology of Animals at the University of Tartu.
On average, Estonian women outlive men by 11 years – but why? Sociologists and demographers point to self-destructive behaviours in men, as well as their greater risk of contracting heart disease, but they overlook the underlying causes of these woes.
Since the human lifespan is a result of evolution, providing an explanation for its variability belongs to the domain of natural sciences, more specifically to evolutionary psychology and behavioural ecology. I will try to explain this phenomenon in the discussion which follows.
The theory of sexual selection maintains that the sex that invests more in offspring (almost always the female) cannot reproduce as fast and thus becomes a limited resource to the other sex. This results in a situation in which fertile females are outnumbered by males interested in mating, and therefore, females have an opportunity to be choosy in selecting mates.
At the same time, this situation creates a basis for mating competition amongst males – when there is a shortage of females, each male can increase his reproductive success only at the expense of other males.
Mating competition between males comes in two forms: On the one hand, they have to compete amongst themselves for access to potential mating partners; on the other hand, they need to prove their quality as breeding partners to the opposite sex.
Besides explaining mating and patterns regarding choice of mate, the theory of sexual selection provides explanations as to why men and women differ in their ways of feeling and thinking, their consuming habits, health status, causes of mortality, and life span.
Men and women have evolved to solve different problems in the context of reproduction and mating. The shorter lifespan of men is an inevitable result of their competition-based reproductive strategy.
Here we are dealing with a vicious circle: In order to attract women men have to compete with each other for authority, status and material resources. The chances of both winning and losing in this game are greater for men, as their reproductive success varies more than that of women. This is why men are programmed to behave in a riskier manner than women.
A risk-prone lifestyle inevitably entails higher male mortality due to accidents, violence and infectious diseases (testosterone, the male sex hormone that induces ‘macho’ behaviour, is immunosuppressive, which in turn causes greater susceptibility to many infectious diseases in males).
In addition to risky behaviour, it is also possible to impress potential breeding partners and competitors by showing off material resources; obtaining these resources (by honest means) offers ample opportunity to work oneself to death.
From the fact that the lifespan of men has evolved to be shorter than that of women, it inevitably follows that all behaviours that potentially increase mating success at the expense of longevity are also adaptive (i.e., useful) to them. Why waste one’s resources living to an old age (which is unlikely anyway) while these resources are badly needed in mating competition at a younger age?
All the differences between the sexes that we can observe in Estonian society (and elsewhere) – both in longevity as well as income – are perfectly consistent with the theory of sexual selection. For example, male over-representation in high-profile and highly paid jobs doesn’t necessarily mean that they are better at such jobs than women. It is just that, for evolutionary reasons, men are simply more motivated to work in such positions, since possession of resources has always offered men more opportunities to convert those resources into reproductive success than it has to women.
Certainly, male behaviour could also be explained by culturally indoctrinated gender roles, but we need to acknowledge that these gender roles are perfectly consistent with the theory of sexual selection. So, parents who raise their sons differently from their daughters behave adaptively.
The high sales of luxury cars is also proof of the extreme intensity of sexual selection prevalent in Estonia. The main function of a luxury vehicle (and all luxury in general) is to advertise the resources owned by the individual both to potential breeding partners as well as competitors. In principle, it is the same type of costly adornment as the tail of a male peacock.
The peacock’s tail is a terrible handicap, which makes it difficult for him to escape from predators in a thick jungle. But this is exactly why the males with large tails are attractive to females: if the peacock can afford to waste resources on such a tail, he definitely must also have resources for other things!
One of the reasons why sexual selection in Estonia is particularly intense probably lies in the ultra-liberal economic environment, which fosters great variability in income and hence resources sought by women and offered by men. In other words, the better the opportunities for accumulating resources, the stronger the competition for them.
Perhaps it is no coincidence that differences in mortality between the sexes started to increase rapidly in all Eastern European countries during the period of post-communist transition to free market economies.
It appears that socialist equalising, which effectively curbed economic inequality within society, was also able to restrain some of the more extreme manifestations of mating competition – there was less incentive for men to work themselves to death, as it was difficult to convert the fruits of one’s labour into visible signals of material resources possessed.
One could speculate that such an even distribution of resources reduced the requirement for showing off with risky behaviour – because material resources were advertised modestly, there was less need to top these through personal bravery. It is possible that the same scenario is at work in today’s semi-socialist Western societies.
But why are differences in mortality between the sexes small in Western liberal market economies? I guess the reason lies in their well-developed class system and more marked social stratification as compared to Eastern Europe.
Unlike in Estonia, where there is not even a clearly developed middle class, mating competition amongst males in liberal Western societies occurs primarily within social classes or strata where the variability of resources is smaller than in the society as a whole.