La. Ebensperger, THE POTENTIAL EFFECTS OF PROTECTED NESTS AND CAGE COMPLEXITY ON MATERNAL AGGRESSION IN-HOUSE MICE, Aggressive behavior, 24(5), 1998, pp. 385-396
I studied the behavior of nursing house mice (Mus musculus) in captivi
ty and used a two-by-two factorial design to test the hypothesis that
the combination of a protected nest along with a chance for the intrud
ers to retreat would improve the ability of resident females to defend
their litters from infanticidal males. A chance for the intruder to r
etreat was manipulated by testing the resident females in either a sin
gle- or a two-compartment cage. The effect of a protected nest was exa
mined by providing females with a nest box having a narrow entrance. D
uring each test, an infanticidal adult male was introduced into the ca
ge of a resident female and her pups. I observed that neither the pres
ence of a protected nest nor the chance for the intruders to retreat t
o a different compartment, or a combination of the two, increased the
ability of a female to defend her litter against an intruder male. Mor
eover, neither of these two factors influenced the overall behavior of
the resident females. I obtained similar results after using data fro
m previous studies to examine the influence of both of these factors o
n the efficiency of maternal aggression. Overall, these two approaches
showed that females are often unable to prevent intruders from commit
ting infanticide. I discuss the validity of the hypothesis that matern
al aggression evolved as a mechanism to protect offspring from infanti
cide. (C) 1998 Wiley-Liss, Inc.