I suppose (but I am just a layman) that animals do not really have any sense of time.
They can express "I am hungry" or "I am extremely hungry" but they cannot express "I have told you I am hungry for the last 20 minutes" because they have no conceptual model for "things as they were 20 minutes ago".
This does not mean that they have no ability to learn (including learning to recognize humans) but for them I suppose it is just a bunch of "state" which classify me as "nice guy who feeds me" or even just "I know I can trust him not to be a menace" but they have no way to reminisce about when we met for the first time, etc.
("Future state" is probably even more inscrutable to them - they have strategies to cope with the present, some ingrained as instinct, some learned "by experience" but I sincerely doubt that they can contemplate something like "tomorrow I will try doing this").