U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

January 2003


We investigated the influence of chemical signals derived from different sources—urine of feral cats (Felis catus) and urine from overcrowded mice (Mus musculus) on regulation of oestrous cycles in Mus musculus musculus under laboratory conditions. Cat urine and urine from mice housed in overcrowded conditions caused very similar effects. Application of urine from feral cats and from overcrowded conspecifics to the bedding of experimental animals for a period of 21 days caused a significant increase in numbers of animals with extended oestrous cycles. Application of cat urine or overcrowded mouse urine to the bedding of female mice caused an extension of oestrous cycles in 56.0% and 62.5% of tested animals, respectively. The results of the present study and other experimental data from our laboratory may indicate that predator urine and urine from overcrowded conspecifics share the same chemical information.