A visitor to our clinic once asked the following: “I have two litter mates that are 2 years old. They get along great. My previous cats were also litter mates, and got along famously until they were 3. Then the fighting started and lasted over 15 years. Why did this happen and what can I do to prevent it?”
First, for the record, adopting siblings together is a great idea. They are already bonded together, and they have similar energy levels so that they can play as much as they wish. People often ask which is best to get, males or females. Both are great, but there is information to suggest that 2 males are best together, followed by a male and female, and lastly 2 females. This is of course a general statement and I personally have seen 2 females, Cleo and Sheba, get along well for the 20 years that they were together!
There are some steps that we can take to provide the pair with the best situation, but unfortunately, there are other situations that we may not have control over. For example, I saw one pair of female cats that were so affectionate together until they were 11 years old; at that age, one of the cats saw a strange cat sitting outside a window and screamed. The sibling came running to see what was the matter, and a case of redirected aggression occurred – the cat that saw the strange cat attacked her sibling since she couldn’t get at the cat outdoors. For the rest of their lives, they avoided and even hissed at each other. Other examples of situations we cannot avoid are often a loud noise outside or something else that frightens one of the cats that we have no control over – and often it happens when we aren’t present to recognize what caused the problem.
Sometimes kittens that have been best buddies will prefer not to be together (or at least as much) when they reach social maturity, which in cats is between 2-4 years of age. Providing separate cat beds and more than one place to perch will allow them to have their own space, and choose when to be together with the other.
In addition, reward them for any positive interactions together. Never force the cats to be together or look at each other because that will only backfire! And I can tell you from my own experience early on that pampering a cat that “gets picked on” can reinforce that cat to act the victim so that they can get the attention. Once, I came home early from work because I was sick. I saw my cats sleeping together. As soon as they saw me, they hissed at each other and went their different directions! From that day forward, I ignored the one when she acted like the victim, and rewarded any positive interactions, and they became best buds.
Do your cats get along? If not, questions are welcome.