Oh how sweet Jos! It's true, animals can love each other. My veterinary nurse/shepherdess neighbour tells me her sheep make firm friends with a selected pal. Pairs or trios, always together and cuddle down in their straw at night with their 'friend' close and snuggly!
All the cats we've ever had used to be much closer friends with one than with another. Minty and Murphy, although litter mates, weren't all that keen on each other. And SmokeyPokey was rather a 'loner' than a matey type. But SimpsonSamson and Gussie (one a Siamese and the other a pedigree British Black Shorthair) were very close pals.
I've posted on here before how Sam the Skull (Spirit) hated every cat he clapped eyes on, until he began sitting with me on The Bench. He accepted Smokey eventually and they'd smile at each other in a chummy sort of way. I miss them both so much. Hope they're exploring Heaven together now!