Animals have built-in mechanisms by which they recognize their own. Memory plays a big role in this. Their DNA is a blueprint by which every instinct in every habit is mapped. There is scarce information on the Internet about how animals recognize their own; therefore to get a clearer picture one must believe they are modeled after humans. Or to be more scientific, instinct among each group according to their functions and their peculiarities is something only each species knows for sure. In other words if they don't have the same characteristics, they're not of their group and can be considered a creature of another kind.
In an article entitled, "Kin Recognition", by Chris Davis, the author concludes that humans don't often know their own kin, so how can animals expect to know theirs.
The answer is memory, and to 'written down' clues and other hints placed here and there. Would humans know their own mother if they had never seen her, if they had been taken away at birth? Of course they would not know her even if they were to share a seat with her on a plane.
It is the warm snug feeling that the human baby gets from mother's first embrace that gives a clue to her importance. The mother clung and fed her baby; soon the mother was recognized, and snuggling up to her breast and getting fulfilled was heaven.
Even if man or animal is less lucky and was never nursed, she is known by her tender loving care and her being there for us at our every whimper. Man was designed that way. Soon man learned others were important to them as their own circle of friends and family grew larger. Man also learned who to fear and what to fear, and all because of never having met them before, or because of not liking what they were.
Since humans are only a rung or two above the animals don't they share characteristics? Certainly. How then do animals recognize their own? They do it by memory. They do it by written down messages and they do it by being told by mama and papa bear "This is your uncle, but he is no good, avoid him. This is a friend of your mama's, she is not related, but she is good. That sly fox peeking through the bushes is no good, climb a tree."
Wait. What about written down messages? Animals don't write. Oh yes they do. They leave their urine scent on trees, on telephone poles and elsewhere. They read by their nose and they use their eyes to spot rabbits and their family when they are away and when they are coming home. All of themselves that they leave in out of the way places, or on your carpet, tell something about them. They memorize the scent.
Animal species are not endowed equally. Some, like certain birds that live mainly above ground, use sounds as their way of telling their own. They do, have well developed memories. They remember where they built their summer homes and have no problem finding them the next year when its time to migrate.
Animals are designed as to their needs; and their survival modes are built in. As for remembering, how else can they do so without memory