The Impact of Hysterectomy in an Urban Colony of Domestic Cats (felis Catus Linnaeus, 1758)

The easiness with which urban cats form colonies and the exponential growth of these populations are a challenge for all known population control methods. The zoological garden of Rio de Janeiro (RIOZOO) has been dealing unsuccessfully with the issue of stray cat populations for more than 10 years. For this reason, it was decided to investigate the structure and composition of the colony of cats populating the RIOZOO and to observe, during 36 months, the impact of hysterectomy of adults, with conservation of the gonads, as a means of population control. Hysterectomy was meant to be performed biennially, though at the beginning of the program, it was performed yearly for 2 consecutive years. The total size of the colony was estimated each year using the capture-mark-recapture technique. During the study's entirety, a total of 96 cats, 80 adults and 16 kittens, were caught. The yearly population estimate of cats showed that between the years 2001 and 2004, the population stopped to grow, strongly tending to decrease. The conserva