Species Description: Feral house cats, Felis catus, are often overlooked in discussions of exotic nuisance animals due to their ubiquity and our familiarity with them as companion animals. They are, however, among the most ecologically damaging introduced animals worldwide.
Domestic cats are characterized by a number of well-known physical characteristics. These include a flexible and compact body, keen eyesight and adaptations for visual acuity at night, retractable claws, sharp teeth and a reduction in numbers of teeth (e.g., the hind chewing teeth) reflecting adaptation as a carnivore, long vibrissae (whiskers), and a long and flexible tail important as an aid to balance (LaBruna 2001, ISSG).
F. catus is among the smaller members of the felid family, but shares with other family members the trait of being an agile and efficient predator.
Potentially Misidentified Species: The only felids native to Florida are the bobcat, Lynx rufus and the highly endangered Florida panther, Puma concolor coryi. Bobcats grow to around twice as large as Felis catus, and their distinctive black bar-shaped markings on the forelegs and black-tipped, stump tail allow easy differentiation between the species. Confusing a feral domestic cat for a Florida panther is unlikely.
Regional Occurrence: Domestic Felis catus are believed to be the results of several millennia of human domestication of one or both of two closely related wild species, the European wild cat, Felis silvestris (probable ancestral line), and the African wild cat Felis lybica. The area of original domestication is believed to be centered in or around Egypt.
Domestic and escaped feral F. catus are now distributed worldwide, notwithstanding a few isolated islands where the species has either not been introduced by humans or has failed to become established (LaBruna 2001).
IRL Distribution: Feral Felis catus are well-established throughout the state, including the 6 IRL watershed counties. A number of feral cat colonies comprised of often large numbers of so-called "TNR" cats (individuals that have been trapped, neutered or spayed, and released into the colony population) are also located in the IRL region.
Age, Size, Lifespan: The life expectancy of feral cats is considerably shorter than that of their house-kept counterparts, between 2 and 3 years of age for feral animals versus 10-15 years or longer for house cats.
The average head and body length of adult Felis catus is around 46 cm and the tail length averages around 30 cm. Adult feral cats typically weigh 3.3-4.5 kg, with males being at the larger end of the range and females at the lower end (ISSG).
Abundance: There are an estimated 10 million owned house cats in Florida. The Florida Fish and Wildlife Conservation Commission has estimated that the feral cat population in Florida is roughly on the same order, i.e., between 6 to 10 million animals (FWCC 2001).
The estimated U.S. population of feral cats is 60 million (ISSG).
Reproduction: As with all mammals, reproduction in Felis catus is sexual and fertilization is internal. Reproduction occurs year-round where resource availability permits.
Relative to other members of the mammalian order Carnivora, F. catus exhibits a high fecundity. This is largely related to the rapid onset of sexual maturity in females, typically between 7-12 months of age, and the capacity for females to come into estrus as often as 5 times a year (Ogan and Jurek 1997, Gunther and Terkel 2002). Females can produce as many as 3 litters in a year (Fitzwater 1994).
Embryology: Gestation lasts for 63-65 days. Litter size typically averages 4-6 young ( O'Donnell 2001).
Temperature: Felis catus is a highly adaptable species, but laboratory animal husbandry authorities suggest an optimal temperature range of 17-29°C.
As with other mammals, feral cats alter daily and seasonal foraging and activity patterns in response to environmental temperature shifts.
Trophic Mode: Felis catus is a predatory carnivore that readily preys on birds and small mammals as well as reptiles, and amphibians. LaBruna (2001) suggests that house cats have retained their instinctive hunting skills to ensure that specific nutritional requirements for fresh animal protein are met.
Associated Species: Association between Felis catus and human caregivers has occurred for perhaps 4,000 years.
Invasion History: Domestication of Felis silvestris and possibly Felis lybica began around 4,000 years ago in Egypt. Domesticated Felis catus can readily interbreed with both of these to form viable (fertile) offspring. In fact, recent mitochondrial DNA studies suggest that both F. lybica and F. catus shuld be considered subspecies of F. silvestris.
Human-aided spread of Felis catus was facilitated both by the animals' beneficial mousing skills and the fact that Egypt was an important trading port in the ancient world. The Egyptians took cats with them on shipping vessels to keep rodent populations in check, and they likely introduced domestic cats to Europe in this manner. In turn, expansion of the Roman Empire and, later, European missionary zeal facilitated the spread of domestic cats into Asia and beyond.
Modern house cats keep feral cat numbers high through escapes and through high fecundity and multiple estrous cycles of females.
Potential to Compete With Natives: LaBruna (2001) estimates that over a half-billion birds a year are killed in the U.S. by a combined feral and outdoor-kept cat population estimated at more than 90-million animals. Dewey (2005) notes Felis catus has been directly responsible for declines in a number of bird and mammal populations, especially small island populations.
Possible Economic Consequences of Invasion: Domestic house cats have significant positive economic value for companionship and for vermin control. In the feral Felis catus population, however, these positives are outweighed by the ecoolgical damage these animals can cause.
In addition to the ecological impacts, Felis catus carries a number of diseases that are transmissible to humans, including rabies, cat-scratch fever, and various parasitic infections (Dewey, 2005). Efforts to manage feral cat populations are costly, and the partial solution of TNR feral cat colonies is controversial.
F. catus species has been nominated as among 100 of the "World's Worst" invaders by the Invasive Species Specialist Group (ISSG).
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Fitzwater W.D. 1994. House cats (feral): Prevention and control of wildlife damage. Cooperative Extension Division; Institute of Agriculture and Natural Resources, University of Nebraska- Lincoln, United States Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control and Great
Gunther I., and J. Terkel J. 2002. Regulation of free-roaming cat (Felis silvestris catus) populations: A survey of the literature and its application to Israel. AnimalWelfare. 11:171-188.
Florida Fish and Wildlife Conservation Commission. 2001. impacts of feral and free-ranging domestic cats on wildlife in Florida. Public education document, published November 2001. 4 p.
LaBruna D. 2001. Introduced species summary project: Domestic Cat (Felis catus). Available online.
O'Donnell C. 2001. Slowing down A CAT-astrophe: Keeping pet cats indoor. Connecticut Audubon Society.
Ogan C.V., and Jurek R.M. 1997. Biology and ecology of feral, free-roaming and stray cats. Pages 87-92 in: J.E. Harris, and C.V. Ogan, (eds.). Mesocarnivores of northern California: Biology, management and survey techniques, workshop maual. 127 p.