The question of whether monkeys “steal” babies touches upon a complex and often misunderstood aspect of primate social behavior. Scientific observation confirms that primates, including monkeys and apes, do engage in the act of taking, carrying, or attempting to care for infants that are not their own offspring. This phenomenon is a documented occurrence across many species, though the motivations and outcomes vary dramatically from the human concept of theft. Understanding this behavior requires examining the underlying biological and social context of the primate troop.
Defining Primate Infant Kidnapping
The behavior often termed “infant kidnapping” is more accurately categorized by primatologists as either allomothering, misdirected maternal behavior, or, in rare cases, a form of aggression or predation. Allomothering, or alloparenting, describes any form of care provided to an infant by a non-parental group member. When this attraction becomes intense and results in the forceful removal of the baby from its biological mother, it crosses into what is specifically defined as a kidnapping event. These incidents are generally temporary, driven by social or reproductive impulses.
The distinction between a social kidnapping and a predatory act is important. In most cases of social kidnapping, the intent is not to harm or consume the infant, but to hold and carry it. Conversely, when large primates like chimpanzees target the infants of other monkey species, the action is purely predatory, as the infant is taken as food. The most publicized incidents involving human infants generally fall into the category of opportunistic or defensive behaviors by primates habituated to human presence.
The Species Known for This Behavior
This infant-taking behavior is widely observed in Old World monkeys, particularly those that live in large, complex social groups. Macaques and baboons, known for their elaborate social structures, are frequently documented engaging in forms of infant handling and, occasionally, coercive removal. Patas monkeys have also been observed in rare instances of a neighboring group’s members kidnapping and attempting to care for an infant.
More recently, a bizarre and unique example of inter-species kidnapping was documented in a group of capuchin monkeys on a small Panamanian island. These capuchins were seen abducting the infants of howler monkeys, a completely different species. This highly unusual behavior, which appeared to spread through the male capuchin group, was not linked to predation or maternal instinct, but rather seemed to be a newly developed social tradition within that isolated population. Among great apes, bonobos have also shown instances of intra-species kidnapping, which can sometimes result in the infant’s death due to dehydration.
Behavioral Drivers for Taking Non-Kin Infants
The motivations behind a primate taking a non-kin infant are varied, ranging from reproductive practice to social maneuvering. One primary driver is misdirected maternal behavior, which occurs when young or inexperienced females, especially those who are not lactating, are strongly attracted to infants. They attempt to hold and care for the baby as a form of practice mothering. This drive is so strong that it can sometimes manifest as “aunting-to-death,” where a non-lactating female forcibly retains an infant until it starves.
Social status also plays a significant role in some species, where having an infant can be used to gain attention or forge bonds with the mother or other high-ranking group members. In these cases, the infant becomes a social prop, temporarily elevating the status of the handler within the troop hierarchy. Stress or social instability within a primate group has also been theorized to contribute to aberrant behaviors, including the non-adaptive removal of infants. True predation, such as when chimpanzees hunt and consume the infants of other monkey species, is motivated purely by nutrition.
What Happens to the Taken Infants
The outcome for an infant that has been forcibly removed from its mother is almost always negative, even when the initial intent is not harmful. The most common result of a kidnapping event, particularly when the non-parental handler is inexperienced or non-lactating, is abandonment or injury. Infants require constant care and regular nursing, and a non-lactating or stressed handler cannot meet these fundamental needs. This lack of proper care frequently leads to death by neglect or starvation rather than direct aggression.
The abducted howler monkey infants in the capuchin study, for example, all died, likely from starvation, despite the capuchins showing no predatory or aggressive intent toward them. On rare occasions, particularly when an infant is orphaned, successful adoption does occur, usually by a close relative or a female with a strong maternal drive. This long-term integration is the exception, not the rule.