Updated January 3, 2021
(Adapted from “Dogs have Owners, Cats Have Staff” seminar by Dr. Patricia Mc Connell, PhD)
If at all possible have the new cat spayed or neutered prior to introduction. If possible wait four to six weeks after spay/neuter before bringing cat home. All cats in the household will get along better if all are spayed and neutered.
Have at least one more litter box than you do cats, and/or one more litter box than levels in your home.
Do not change cat litters if possible. Cats become accustomed to one litter and may eliminate outside the box if the litter is changed, especially if the change is sudden.
1. Completely separate resident cats and the new cat for one to two weeks.
Keep the new cat in separate room with large gap under door, so that cats can smell and hear each other. Allow cats to play with each other’s paws under the door. If play becomes too rough or injury occurs, place a towel or blanket loosely over opening.
The new cat should have same litter box, litter, food and food/water bowls that he/she had previously if at all possible.
A Sentry Cat Calming Diffuser (this is lavender, chamomile and kitty pheromone combined, and tends to work better than the Feliway Diffusers) , one in the new cat's room and one in the area most utilized by the resident cats, may help to calm everyone.
During the second week, give a blanket, toys or scratching post used by the new cat to the resident cat(s). Take a blanket or other items used by the resident cats and place it in the room with the new cat. This exposes each cat to the other’s scents.
2. After one to two weeks, allow the new cat to roam the house alone, with other cats restricted or removed for short periods of time. This allows the new cat to become used to the scent of the home and the resident cats, as well as mark the house by rubbing and pawing.
Use a squirt gun to shoot water at the new cat if he/she urinates/sprays or claws on the wrong items or in the wrong areas.
Sentry Cat Calming Spray may be used on scratching posts and toys to encourage the new cat to use these items.
Gradually increase the time allowed for the new cat to “explore” your home alone. Begin with 5-10 minutes 2-4 times a day. Gradually increase time to 1 hour 2-3 times daily.
3. Once the new cat appears calm (purring, quietly meowing, rolling and playing or sleeping) outside of his/her room; allow all cats together for short periods of time. Be sure that all cats have ways of escaping and places to hide if threatened. Cat condos or several large cardboard boxes in numerous places work well for this.
If there is more than one resident cat, allow one resident cat at a time to meet and interact with new cat. When two cats are comfortable with each other, gradually introduce second or third resident cat to the newcomer.
If hissing, spitting or other aggressive behavior occurs, allow it for a few seconds. If cats do not leave each other alone, then separate them. Always remove and isolate the new cat, so that the resident cat(s) feel secure in his/her/their territory. The new cat can be safely removed by scruffing and lifting him up (Ask about the best way to pick up and carry an upset cat.) or by throwing a towel over the cat and scooping him/her up like a steam shovel. (Ask for a demonstration of this technique.)
If fighting occurs, use a squirt gun or loud noise (such as banging pots and pans) to break up fight. Immediately remove and isolate the new cat.
This phase of introduction should continue until all cats appear comfortable with each other.
Placing cats in two adjoining rooms with a baby gate between them sometimes works while during this phase. The cats can see/touch/smell/hear each other. Fighting should be minimized due to the need to climb or jump over the baby gate.
Feliway Diffusers may also be used to calm all cats during this introduction.
This phase may last two to 10 weeks. Be patient and ask for professional help (behaviorist, veterinarian or veterinary staff member with behavioral training).
Marie Seelmeyer BS VT
Canine and Feline Behavior Counselor