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Population modeling demonstrates TNR’s potential to reduce free-roaming cat numbers


“Simulating Free-Roaming Cat Population Management Options in Open Demographic Environments,” published in PLoS ONE, 2014. Complete article available (open access) online here.


In this study [1], a diverse team of researchers from the fields of animal welfare, wildlife conservation, and veterinary medicine used sophisticated population modeling techniques to examine various lethal and non-lethal methods for managing free-roaming cats over a 50-year period.

Key points

The modeling described in this study is the first to account for the movement of cats in (e.g., through abandonment) and out (e.g., through natural dispersal) of a given area, an important element that more accurately reflects real-world conditions.

Results show that reducing free-roaming cat populations in large urban areas can be accomplished either by removing 20% of the population every six months or by sterilizing 30% of the fertile component of the population every six months [1].

Reducing free-roaming cat populations can be achieved by sterilizing at least 30% of the unsterilized segment of the population every six months.

Although an effective temporary contraceptive is not yet available for use in cats in the U.S., this option was also evaluated. Results indicate that at least 50% of the fertile component of the population would need to be contracepted in order to reduce free-roaming cat populations [1].

The study’s authors note that the abandonment of cats “significantly reduce[s] the effectiveness of any management intervention” [1]. In addition, they point out that their population modeling considers key biological processes “for determining optimal solutions for [free-roaming cat] population management, but economic, social and other considerations also will factor prominently into the final choice(s) among multiple management options” [1].

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  1. Miller, P.S.; Boone, J.D.; Briggs, J.R.; Lawler, D.F.; Levy, J.K.; Nutter, F.B.; Slater, M.; Zawistowski, S. Simulating Free-Roaming Cat Population Management Options in Open Demographic Environments. PLoS ONE 2014, 9, e113553, doi:10.1371/journal.pone.0113553.


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