![]() Not only is releasing cats a risk for wildlife, but it also invites welfare concerns for the cats themselves. Yet some densely populated cities such as Chicago, IL., USA are widely reported in the media ( Glanton, 2017) as making mass efforts to use cats as rat control tools. These rats are well adapted to urban ecosystems they represent a large prey item for all but the boldest cats and can defend themselves. In contrast to the native vertebrates most impacted by cats, city rats have coexisted with cats for centuries. At current rates of human urbanization, the latter are the fastest growing ecosystems in the world, with more than 70% of people expected to live in cities by 2050 ( Zhou et al., 2013). This has been historically recognized on island ecosystems where cats are evolutionarily novel ( Woinarski et al., 2017), but is also true for some continental ( Loss and Marra, 2017) and urban systems ( Pillay et al., 2018). For example, in Australia ( Davies et al., 2017) and the US ( Loss et al., 2013), cats represent the greatest source of anthropogenic mortality for native birds and mammals. The domestication of cats, and abundance of easier to obtain alternative foods cast doubts on cats' inclination to prey on city rats and suppress their numbers.įeral cats can impact on the dynamics of their prey, but there is much stronger data indicating that cats influence native wildlife ( Kauhala et al., 2015 Kikillus et al., 2017) than city rats. Further, as domesticated animals, cats are well adapted to survive on handouts from people ( Montague et al., 2014). And thus, cats may be more likely to deplete birds and easier meals (e.g., smaller mammals and their young) before moving to rats. However, predators have an energy budget, whereby their caloric intake is maximized ( Jeschke et al., 2002) against potential risks from large or defensive prey ( Embar et al., 2014). This misconception may be partly responsible for cats being widely considered as a “natural” control tool for rats. Many non-trained observers, however, cannot tell the difference between mice which weigh 20–35 g ( Zielinski et al., 1992) and city rats which often weigh 10 times as much ( Parsons et al., 2017 Combs et al., 2018). I frightened a little mouse under her chair.Ĭat predation on rodents, particularly mice ( Mus, Peromyscus spp.), is among the most recognized models of predator: prey interactions, inspiring nursery rhymes, cartoons and public perceptions. Our findings that cat presence led to fewer rat sightings may explain the common perception of their value as rat-predators despite the associated risks. Even though rats were less likely to be seen, they simply shifted their movements and remained present in the system. ![]() Our findings of low levels of predation support why ecologists believe the risks to native wildlife outweighs any benefits of releasing cats. For every additional cat sighting, a rat is 1.19 times more likely to move in the direction of shelter. Logistic regression showed the likelihood of a rat being seen on a particular day is associated with the number of cats seen on the same day (OR = 0.1, p < 0.001) or previous day (OR = 0.15, p < 0.001). There were three instances of predation and 20 stalking events. From through we captured 306 videos of pre-identified cats and/or rats that shared the same space. We used a pre-existing radiofrequency identification assay (microchipped rats and field cameras) and ethograms to assess the impact of cats, including temporal and space use patterns, on an active rat colony. However, cats prefer defenseless prey, and there are no data suggesting that cats influence large (>300 g) urban rats. Cats can influence their prey directly by killing or indirectly through changes to feeding or space-use. Despite these risks, cats are commonly released as control agents for city rats ( Rattus spp.). 4Department of Biological Sciences and the Louis Calder Center-Biological Field Station, Fordham University, Armonk, NY, United Statesįeral cats ( Felis catus) are predators that cause widespread loss of native wildlife in urban ecosystems.3Medical and Applied Entomology, Arrow Exterminating Company, Inc.2School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia.1Department of Biological Sciences, Fordham University, Bronx, NY, United States.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |