Female mammals kill the offspring of their competitors when resources are scarce

JULY 15, 2019

by Max Planck Society

Dieter Lukas and Elise Huchard have now looked into infanticide by female mammals. In previous studies, males have been found to kill when females will not mate with them if they are still caring for an offspring sired by their previous partner. "Across mammals, females are more likely to commit infanticide when conditions are harsh and when having offspring is particularly costly to females," says Huchard. "The potential triggers and likely benefits of infanticide however appear to differ according to the specific circumstances."

Infanticide can remove potential competitors

The researchers found that when females are territorial and need access to breeding space or burrows, infanticide can cause neighbouring females to leave so that killers may expand their territory. When females come together on breeding grounds, females might commit infanticide to prevent other offspring from stealing their milk. When females live in groups with others who care for offspring that are not their own, infanticide increases the help that their own surviving offspring receive. And when females live in stable social groups, infanticide can remove potential competitors for access to status or resources. "All these circumstances have in common that infanticide occurs when the proximity of offspring born to other females directly threatens the killer's reproductive success by limiting access to the resources that are most critical for her own offspring: access to breeding space, milk, offspring care, or social status," says Huchard.

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