In a 2021 study published in the journal eLife, researchers examined the effects of mother loss on young mountain gorillas (Gorilla beringei beringei) and found that orphans older than 2 years of age build relationships with other group members, especially dominant males.
In animal husbandry, the practice of replacing children is also widespread. If one female has a non-viable or small offspring, you can plant children from the multiple litter of another mother to her. Cats, dogs, rabbits and birds perfectly bring up other people's babies and do not pay attention to external differences.
Nevertheless, of course, most of the stories of feeding a variety of alien cubs are associated with dogs. Mother dogs take under their care a variety of babies: for example, a raccoon, an opossum, the same squirrels, kittens.
There are quite numerous facts of feeding squirrels, puppies of different breeds by a cat.
Just bring the kitten into the room and go to play with him. If the baby has already adapted to the person, you can begin to open the door. This way the cat will be able to see that you are talking to the kitten. Now, you need to call the cat to him and treat her with a treat.