This blog post examines the possibility that rape functioned as a reproductive strategy in past environments from a biological perspective. It analyzes the evidence supporting this claim through situations of weakened norms and animal case studies.
There is no doubt that rape is a heinous crime and morally wrong. However, this article does not address the moral perspective; instead, it examines whether rape is an adaptation from a biological standpoint. An adaptation refers to “a feature or behavior that has evolved to be advantageous for survival and reproduction in a given environment.” As explained in Darwin’s “On the Origin of Species,” natural selection induces survival competition among individuals of the same species based on fertility and variability, ensuring only those best suited to their environment survive and reproduce. For example, desert foxes living in hot regions adapted to effectively dissipate body heat by becoming smaller in size and developing larger ears, while Arctic foxes in cold regions evolved larger bodies and smaller ears to minimize heat loss.
According to this definition of adaptation, to determine whether rape is an adaptation or merely a byproduct of sexual desire, we must examine whether rape actually aids species preservation, i.e., reproduction. In modern society, rape may not aid reproduction. Even if a woman raped becomes pregnant, a significant number would choose abortion, and the perpetrator faces a high likelihood of long-term imprisonment. Under the South Korean legal system, rapists are also isolated from society for extended periods, meaning their subsequent reproductive opportunities are severely limited. However, a crucial point is that biological changes cannot keep pace with the rapid institutional changes of modern society. In the past, there were periods when punishment for rape was weak or non-existent. In such eras, rape may have actually aided reproduction for men who otherwise lacked reproductive opportunities.
Those holding opposing views may question whether rape was truly frequent in environments with minimal norms, such as primitive times. However, examining ‘quasi-primitive states’ where norms are weakened, such as modern warfare, reveals that rape becomes significantly more frequent than in peacetime. The phenomenon of increased rape when the efficacy of norms is greatly reduced suggests that even in primitive times, when norms were nearly absent, rape likely provided some benefit to male reproductive behavior and may have sometimes become a dominant reproductive strategy.
Conversely, opponents might question why some animal species engage in rape while others do not, if rape is adaptive. Two possibilities can be considered. The first is when males are so powerful, like lions, and dominate the group that reproduction is possible without rape or active courtship. The second is when females are significantly larger and stronger than males, making rape attempts impossible. Indeed, in many fish species, females are larger than males, and among insects like praying mantises, larger and stronger females are common.
In species that engage in rape, there are even cases where specialized organs have evolved for this purpose. The ground beetle is a prime example. While most male ground beetles prepare courtship gifts for females, some males bypass courtship entirely. They use pincers-like genitalia to grasp the female’s wings or legs and force copulation. Given the female’s persistent attempts to escape during mating, this constitutes clear forced copulation, and in this case, the male’s reproductive organs can be seen as having evolved for rape. Furthermore, females are known to have developed reproductive defense mechanisms to block sperm introduced through unwanted forced copulation, demonstrating that both sexes have adapted to ‘reproductive competition surrounding rape’.
Based on such cases, re-examining whether rape is an adaptation or a byproduct of sexual desire makes it difficult to dismiss the possibility that rape may have provided practical benefits for reproduction. The increased frequency of rape in environments where norms weaken, such as war, and the existence of species like the ground beetle, which have developed specialized organs for rape, suggest that rape may have evolved not merely as a product of sexual desire, but as an adaptive strategy for reproduction. Therefore, the conclusion that rape is adaptive holds a certain degree of persuasive power from a biological perspective.
