Data from: Conditional fetal and infant killing by male baboons

Sexually selected feticide—the death of infants in utero as a result of
male behaviour—has only rarely been described or analysed, although it is
presumed to be favoured by the same selective pressures that favour
sexually selected infanticide. To test this hypothesis, we measured the
frequency of feticide and infanticide by male baboons of the Amboseli
basin in Kenya, and examined which characteristics of a male and his
environment made him more likely to commit feticide and/or infanticide. We
found a dramatic increase in fetal and infant death rates, but no increase
in death rates of 1- to 2-year-old individuals, following the immigration
of males who stood to benefit from feticide and infanticide. Specifically,
fetal and infant death rates were highest following immigrations in which:
(i) the immigrant male rapidly attained high rank, (ii) that male remained
consistently resident in the group for at least three months, (iii) food
availability and social group range overlap was relatively low and (iv)
relatively many pregnant females and/or dependent infants were present.
Together, these results provide strong evidence for the existence of both
sexually selected feticide and infanticide in our population, and they
indicate that feticide and infanticide are conditional male behavioural
strategies employed under particular circumstances.