«Kitten season is, as the name implies, the time of year when unspayed female cats have most of their kittens,» said Dr. Frank McMillan, DVM, director of well - being studies for Best Friends Animal Society. (petsinthecitymagazine.com)
Unspayed female cats often knead right before going into heat. (mnn.com)
In unspayed female cats, mammary gland tumors are less common than in dogs, but 85 % are cancerous and deadly. (standforanimals.org)