This study investigated the influence of cat urine odour in suppressing dev
elopment and fertility in Campbell's hamster males. Exposure to this odour
from postnatal day 11 until day 45 (sexual maturation) resulted in reduced
sex organ weights, reduced testosterone levels and in an increase in abnorm
alities of the synaptonemal complex in both sex chromosomes and autosomes.
Subsequent breeding experiments revealed a significant decrease in litter s
ize. All these data indicate a severe effect of predator odour on the breed
ing success of potential prey species. It is assumed that these effects are
caused by the sulphurous compounds in the urine; however, the underlying m
echanisms are not yet known.