Although some cats do enjoy the companionship of other cats, unlike dogs, cats are not pack animals. Unless a pair of kitten siblings are raised together, they are not likely to remember or recognize each other after becoming separated. Even a short separation can be enough to make them forget.
Leaving the Litter
Kittens typically are ready to leave the litter and be adopted by eight weeks of age. By this time, a kitten has formed a strong attachment to her mother and litter mates, and may show signs of missing her family after being separated from them. However, it doesn’t take long for a kitten to reattach to her human family and other pets in the house. Once this happens, the kitten usually forgets all about her mother and siblings and adapts to being a part of her new family. If your kitten shows signs of distress at being separated from her litter, you can hasten her reattachment to you by simply responding to her cries and caring for her as her mother would.
Failure to Recognize
Cats rely primarily on scent for recognition. If one cat smells unfamiliar to another cat, regardless of whether they’re related, the unfamiliar-smelling cat will be regarded as a stranger. This is why even two cats who have spent their entire lives together sometimes act like they've never met. Even a short trip to another location, like the vet’s office, can be enough to cover a cat in unfamiliar scents that cause other cats in the household to react to her as an invader when you bring her home.
Adopting Kitten Siblings
Even though cats aren't sentimental about their brothers or sisters, if planning to get two or more cats, it can be a good idea to get them from the same litter. Kitten siblings already have bonded and established a social hierarchy, which might make them less likely to fight. However, sometimes siblings just don’t like each other and refuse to get along. Adopting siblings also brings the risk that both cats will have inherited the same genetic health issues or behavioral problems. You also should be aware of breed temperament when deciding not only whether to adopt siblings, but also multiple cats in general. Some breeds, like the Siamese, generally prefer to be the only cat in the house and might behave aggressively toward another cat regardless of the circumstances.
Dealing with Aggression
When one cat fails to recognize another and either attacks or displays territorial aggression, there are a few things you can do. It’s best to gradually reintroduce cats who have been separated for even a short time. One way to do this is to keep the returning cat in her carrier, either outside or in a separate room. Rub a towel over both cats multiple times to mingle their scents and encourage recognition before bringing in the carrier. The returning cat should remain in the carrier, out of reach, until all of the cats are calm and acting curious toward one another. Before releasing the returning cat, set the carrier on the floor and allow her and the other cats to smell each other. Once no one is displaying any signs of aggression, it should be safe to let the returning cat out, but you should still keep an eye on the situation. If they do fight, it’s best to distract them with loud noise rather than trying to put yourself between fighting cats.
Jean Marie Bauhaus has been writing about a wide range of topics since 2000. Her articles have appeared on a number of popular websites, and she is also the author of two urban fantasy novels. She has a Bachelor of Science in social science from Rogers State University.