- Males that have newly immigrated or dominant males to a group will sometimes kill or attack infants (Hausfater & Hrdy, 1984; Parmigiani and von Saal, 1994).
- Direct observations of infanticide in free ranging primates has been described approximately 6% of all primate species (Dixson, 2012).
- Hrdy (1974) suggested this was a sexual selective behavior based upon her studies of infanticide in langurs or Asian leak monkeys.
- Killing infants allowed the males to advance the time of the mother’s estrus and allow them to sire the females next offspring thus increasing their ability to carry on their genes (Hrdy, 1974; Smuts and Smuts, 1993)
- Counter strategies (Hrdy, 1979)
- Male and female friendships (Smuts, 1985)
- Opie (2013) suggested that high male infanticide consistently occurred prior to social monogamy across primates. They also found that primates that exhibit monogamy had much lower infanticide rates.
- Other female sexual characteristics
- Sexual swelling
- Multiple mating
- Population density hypothesis
- High population densities lead to high intruder pressures thus the male is unable to monopolize females. This leads to more challenges by other males and possible infanticide by the intruder males (Moore, 1985)
****Dixson (2012) however argues that male infanticide is used to explain several biological processes including such things as sexual swelling and multiple partners
- Some primate groups the exhibit infanticide
- Gorillas (Yamagiwa et al., 2009)
- Chimpanzees (Sherrow and Amsler, 2007)
- Langurs (Hrdy, 1977)
- Ring tailed lemurs (Pereira and Weiss, 1991)
- Baboons (Swedell and Saunders, 2003)
- Gorillas (Yamagiwa et al., 2009)
Borries, C., Launhardt, K., Epplen, C., Epplen, J. T., and Winkler, P. 1999. DNA analyses support the hypothesis that infanticide is adaptive in langur monkeys, Proc. R. Soc. Lond. B 266:901–904.
Dixson, Alan. 2012. Primate Sexuality : Comparative Studies of the Prosimians, Monkeys, Apes and Human Beings. Oxford [England] ; New York: Oxford University Press.
Hausfater, G. and Hrdy, S. B. 1984. Infanticide: Comparative and Evolutionary Perspectives, Aldine Publishing Company, New York.
Hrdy, S. B.1974. Male–male competition and infanticide among the langurs (Presbytis entellus) of Abu, Rajasthan, Folia Primatol. 22:19–58.
Hrdy, Sarah Blaffer. 1977. The Langurs of Abu : Female and Male Strategies of Reproduction. Cambridge, Mass.: Harvard University Press.
Opie C, Atkinson QD, Dunbar RIM, Shultz S. 2013. Male infanticide leads to social monogamy in primates. Proc Natl Acad Sci USA 110(33):13328–13332.
Pereira, Michael, and Mark Weiss. 1991. Female Mate Choice, Male Migration, and the Threat of Infanticide in Ringtailed Lemurs. Behavioral Ecology and Sociobiology. 28, no. 2: 141-152.
Sherrow, Hogan, and Sylvia Amsler. 2007. New Intercommunity Infanticides by the Chimpanzees of Ngogo, Kibale National Park, Uganda. International Journal of Primatology. 28, no. 1: 9-22.
Smuts, B. B. 1985. Sex and Friendship in Baboons, Aldine Publishing Company,New York.
Smuts, B. B. and Smuts, R. W.1993. Male aggression and sexual coercion of femalesin nonhuman primates and other mammals: Evidence and theoretical implications, Adv. Stud. Behav. 22:1–63.
Sommer, V.1994. Infanticide among the langurs of Jodhpur: Testing the sexual selection hypothesis with a long-term record, in: Infanticide and Parental Care, S. Parmigiani, and F. S., vom Saal, eds., Harwood Academic Publishers, New York, pp. 155–187.
Swedell, L, and J Saunders. 2003. Female Reproductive Strategies in Hamadryas Baboons: Paternity Certainty, Infanticide Avoidance, and Copulation Calls. American Journal of Physical Anthropology. 204.
Yamagiwa, Juichi, John Kahekwa, and Augustin Kanyunyi Basabose. 2009. Infanticide and Social Flexibility in the Genus Gorilla. Primates; Journal of Primatology. 50, no. 4: 293-303.