Sexual infidelity has always been a part of human behavior and is also present among many animals that supposedly mate exclusively and for life. Both males and females will frequently have sex outside of their primary mating pairs, and the reason is that sexual infidelity gives a distinct evolutionary edge to animals trying to safely raise as many offspring as possible.
Many animals, of course, do not mate exclusively at all. Animals often live in groups in which one male will mate with many females, or they live solitary lives during which they come together only briefly for mating purposes. The animals that do mate exclusively and remain together in bonded pairs have the advantage of two parents rather than one to both feed and protect babies.
However, while mating in exclusive pairs gives animals a clear advantage, straying from these pairs also provides an evolutionary advantage.
Among male animals, the instinct to father as many children as possible in order to continue his genetic line is overpowering. While mating in pairs can greatly increase the odds that children will survive to reach maturity, mating outside the pair further increases the odds of successfully fathering a large number of offspring.
As a result, while many animals have developed the instinct to mate in pairs for life, they retain the strong instinct to mate with as many females as possible. In most cases, the males will remain dedicated and attentive to just the one female and her offspring, although in some cases (such as the wolverine) males will be attentive mates and parents for as many as three females and her offspring.
Is There An Evolutionary Advantage In Female Infidelity?
But what about females? We now know that females in supposedly monogamous pairs will often have sex with other partners, but for many years it was assumed that they did not. The reason was that female infidelity did not seem to convey any evolutionary advantage. Females can only have so many children at one time, unlike males who can father children with a large number of females at the same time.
However, observation and genetic analysis of various monogamous bird species revealed definitively that females stray nearly as frequently as males. Furthermore, related studies conducted among the Pimbwe women of Tanzania and the Himba women of Namibia found that female infidelity was not only present but appeared to increase reproductive success.
There are various respected theories about why female infidelity also provides an evolutionary advantage. Genetic diversity is an important element of evolutionary success because it increases the odds of producing children who carry the strongest genes. Having children by fathers outside of a primary pair increases a female’s chances of securing good genes for her offspring. It also helps females to guard against the possibility that a primary partner is infertile and unable to father offspring. Furthermore, increasing the number of males who father her offspring can increase the support and access to resources that a female receives.
Don’t Take Commitment Lightly, Because It May Not Come Naturally
So what does this mean for humans, particularly in most Western societies in which the monogamous relationship model is considered to be the only acceptable approach to mating? Human behavior is influenced by much more than instinct and biological imperatives, and infidelity is certainly not inevitable just because it provides an evolutionary advantage.
However, it may be helpful to recognize that infidelity has always been a common—and, in some ways, even a healthy and advantageous—part of human development into the most dominant species on the planet. Recognizing that monogamy appears to be a cultural rather than fundamental component of human behavior may help us to be more aware of and therefore more able to restrain our baser impulses. A relationship is truly a committed choice rather than an inevitable step, and it should be taken neither lightly nor for granted.
“Is An “Infidelity Radar” Real?” – Find Out Now!