They had both been to the vet for their annuals. I called the vet a few days after this started happening, and they suggested that Jada might still smell like the vet and it upset Jack. They told me to get a piece of clothing that I had worn and to rub it on Jack and then on Jada. This didn't...
I got my 2 cats Jada (spayed female) and Jack (neutered male) at the same time about a year and half ago and they are now about 2 years old. They have always gotten along very well, until recently. Jack is acting more assertively (or aggressively) towards Jada. I think he just wants to play...
