The phrase "intact cats" refers to cats that have not been spayed (females) or neutered (males). They still have their reproductive organs and can potentially mate and have offspring. Full definition
If this behavior happens out in a free - range environment with intact cats, or if we see it on a nature program, it's something we understand as normal animal behavior. (catbehaviorassociates.com)
We also found that the estimated percentage of owned intact cats that were spayed or neutered was higher for the 18 - month period in the intervention area than any of the control areas. (file.scirp.org)
Until spaying and neutering pets became available and accessible around the 1930s, keeping intact cats indoors was messy business during mating season. (alleycat.org)