Chemical cues from kingsnakes do not cause inducible defenses in house mice

Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators [Current Zoology 58 (6): 797–804, 2012].