evolutionary psychology familicide infanticide mass killings Mesac Damas step parents

Familicide – Evolutionary Origins

In our last post we reported about the case of infanticide (or fililcide) where a man involved in a bitter custody dispute killed his children and then took his own life. With the reporting of a similar case in Florida, this time representing familicide where the entire family was killed by a parent, I thought perhaps it might be worthwhile to try and understand the roots of this behavior.

Mesac Damas recently killed his wife and five young children and then fled to Haiti where he was caught. Supposedly while awaiting extradition back to the U.S., he confessed to the murders. When asked why he did it he responded “Only God knows”. The murders were especially brutal with Sheriff in charge of the case calling them “the worst of the worst”. Damas had a history of domestic violence and apparently thought his wife was cheating on him with another man.

In a fascinating 1995 paper by Wilson, Daly, and Daniele, the authors delineate some of the characteristics of familicide- i.e cases in which a spouse kills an entire family and sometimes themselves. In an examination of 109 incidents of familicide in Canada and Britain the authors found that familicide is most often perpetuated by men. Half of these male perpetrators killed themselves which is a much higher percentage than men who kill only their wives, or just their children. In cases of familicide the parents are more likely to be living together as opposed to being married. Step children are more likely to be victims of familicide than genetic offspring. However, men who kill step children almost never kill themselves. The authors conclude with a tentative categorization of familicidal incidents into two types – accusatory or despondent. As the authors explain:

The hostile, accusatory familicidal killer is often enraged at the alienation of his wife, and may declare that “If I can’t have her, no one can.”The despondent familicide perpetrator instead appears to believe that his victims could not persist or cope in his absence, and that their deaths are therefore necessary, perhaps even merciful, corollaries to his suicide. In either case, the killer apparently feels entitled to decide his victims’ fates.” p. 15

The Florida case presents many of the characteristics outlined in this paper. The killer was male, he and his wife had been living together for a long time and had only recently been married. He fit the pattern of an accusatory killer who was outraged that his wife may have been cheating on him. What we do not know is whether he suspected that any of his wife’s children were by another man, but it wouldn’t be surprising.

Why would this be important? It is well known that violence against children in a family is more likely to be perpetrated by a step parent. In another paper Daly and Wilson (1994) found that step fathers were more likely to beat step children to death, while genetic parents were more likely to shoot or asphyxiate their offspring. The genetic fathers were also more likely to commit suicide.

As David Buss writes in Evolutionary Psychology: The New Science of the Mind, genetic relatedness is a strong predictor of not only how many resources a child receives but also of how likely they are to be abused. The closer the genetic relationship, the more likely the child is to receive resources and not be abused, while the more distant the relationship the more likely the child is to be abused and not receive resources. This pattern comes from our evolutionary history. Male primates such as chimpanzees are known to kill other males’ offspring which precipitates the females going into heat. The killer males will then mate with the females to produce their own offspring. This pattern of behavior presumably originated in the common ancestor to humans and apes. It had survival value and so continues to be found in humans and primates today.

In her book The Chimpanzees of Gombe: Patterns of Behavior, noted biologist Jane Goodall describes numerous incidents of infanticide by both males and females among chimpanzees. In general she believes that many of the attacks are focused on the mothers of the infants and are related to a distrust and aversion to strangers. Yet males appeared to also attack and sometimes eat infants of females so as to bring the females into heat sooner. Interestedly, young unattached females from other groups were only attacked mildly, while older females who were not in heat and who had infants were attacked quite severely and even killed.

Unfortunately for us, we find these evolutionary patterns of killing writ large in humans. A quick examination of mass killings around the world reveals this pattern in ethnic cleansing and warfare. In World War II, the Soviets raped and killed on a massive scale (the Germans while brutal killers did not commit as much rape). The degree of infanticide and rape during the recent ethnic violence in Rwanda has also now been documented. And of course it is quite easy to find more examples.

This is not to say that step parents are murderers, child abusers, bad parents (most are not) or that in our society familicide is common (it is not). But is does remind us to be aware of the possible pre-cursors to this type of violence and to be cognizant of things that may trigger this behavior.

– Kevin


Davies, N. (2007). No Simple Victory: World War II in Europe, 1939-1945. New York, NY: Viking.

de Brouwer A., & Ka Hon Chu, S. (Editors). (In Press). The Men Who Killed Me: Rwandan Survivors of Sexual Violence. Vancouver, BC: Douglas & McIntyre.

Buss, D. (2008). Evolutionary Psychology: The New Science of the Mind. Boston, MA: Pearson.

Daly M, Wilson MI (1994) Some differential attributes of lethal assaults on small children by stepfathers versus genetic fathers. Ethology & Sociobiology 15: 207-217.

Goodall, J. (1986). The Chimpanzees of Gombe: Patterns of Behavior Cambridge, MA: Harvard University Press.

Wilson M, Daly M, Daniele A (1995) Familicide: the killing of spouse and children. Aggressive Behavior 21: 275-291.

Further Readings:

Publications by Martin Daly and Margo Wilson

child murder infanticide

Infanticide-When Parents Kill Their Children

The recent murder of Jason (12) and Jennifer (7) Mulvaney by their father, James, sparks feelings of outrage and bewilderment because it is such an abhorrent act. Unfortunately the murder of children is seemingly a part of the human repetoire of behaviors. Infanticide was known in prehistoric times and continued through the Middle Ages to the present day. In ancient Egypt infanticide was so great a concern that it was forbidden. During the Greco-Roman period babies were rescued from manure heaps, a not uncommon method of infanticide by Greeks or Romans, and either adopted as foundlings or raised as slaves. Judaism explicitly prohibits infanticide in the Torah.(e.g., Deuteronomy 12:30-31, 18:10; 2 Kings 16:3 & 17:17, 30-31 & 21:6 & 23:4, 10; Jeremiah 7:31-32 & 19:5 & 32:35; Ezekiel 16: 20-21, 36; Judges 11:31) Christianity, too, was concerned with infanticide, and forbade it. (Teachings of the Apostles or Didache said “You shall not kill that which is born.”)[36])In India, Hinduism condemns the act.

Throughout history human cultures have been troubled by the ritual killing of children. The practice appears to have been so wide spread that major religions and cultures adopted laws to forbid it.

The United States ranks eleventh in infanticide of infants under 1 year killed and fourth for those killed from 1 through 14 years. “In Southern California this month, six children have been stabbed by parents. Four have died.”

In Ventura County in 1995 Michael Sasse shot and killed two of his children, ages 3 and 4 before committing suicide. Cora Caro was convicted and sent to death row for shooting to death three of her four sons in 1999 as they slept in their beds, and prosecutors purported that she sought revenge against her husband because of their troubled marriage. Narind Virk was convicted in 2002 but found not guilty by reason of insanity of forcing her children into the cold waters of Channel Islands Harbor and then jumping in herself. All three survived.

How are we to understand these horrific acts and how can they be prevented. Many of these murders share common factors. Married adults are fighting and threatening each other. They challenge the rights of each other to remain parents and retain custody. There is impending or real financial hardship resulting in loss of income, employment and a marked decline in their standard of living. Parents are protective of their children and view their impending suffering of parental loss and lifestyle as so devastating as to become intolerable. To these circumstances you can sometimes add spousal mental and physical abuse, a family history of emotional illness, and a litigious conflict-promoting legal system. This can result in the psychological equivalent of the perfect storm in which the end of life is viewed as the only relief to unrelenting suffering.

As reported in the Ventura County Star, James Mulvaney’s wife had primary custody of the children despite his attending a “positive parenting” class.” On September 4 he lost his job as financial center manager for Citibank in Camarillo. He failed “to save the marriage, to improve and better the children’s education” according to court documents ,despite borrowing $200,000 with his ex-spouse to buy a house in which they lived for seven months.

Mulvaney wanted spousal support from his ex-wife because she made more money. Had someone understood the significance of these events; had someone recognized the destructive power of Mulvaney’s feelings, and had someone known doing something was better than doing nothing, this tragedy might have been prevented.

Marriages will continue to fail and parents will still insist on fighting each other for custody. We are in the midst of the worst economic downturn in our recent history and job loss is expected to exceed 10% of our work force. While this doesn’t explain the tragic deaths of the Mulvaneys, incidents like this seem more prevalent in difficult times, when extreme stress can unlock the inner psychological demons that must be present in someone who commits such an atrocity.