Let's simply the problem first: what is the purpose of animals?

1. To survive
2. To reproduce

Everything else is either a subtask of one of these things or an accidental result of something that used to be purposeful (and thus is not currently purposeful, at least for this particular organism).

You could even define these things as types of awareness, from which true drive emerges. Thus, the awareness itself is fundamental, not the drive. (Some philosophers hypothesize about fundamental "drives" that people have.)

1. Life: you are aware that you are alive *after* you are born, and then you are driven to stay live for as long as you can.
2. Death: you are aware that your death will come, so you are driven to do things *before* you die. The primary motive of every living thing is to reproduce before death and then ensure your kin survives and reproduces. This can be generalized into "making the world a better place".

With this in mind, we could sort life into roughly three stages:

1. Survival only. This is adolescence. We generally consider this to be ages 0-18. In some cultures, it is more like 0-15. Biologically, it is from birth until you reach puberty.
2. Reproduction only. This is the window in which your primary effort is reproduction. Your death awareness has activated, but you also have no kin to support yet, so there's no need to invest in them or "making the world a better place" yet, so everything is about reproduction. This might mean status games, grooming, etc.
3. Survival of self and kin. This is post-reproduction, where you become both a parent and a leading member of the community to help everyone that you want to. You're no longer constrained by the need to reproduce, and you know your survival goals will eventually fail (death), so you aren't even so worried about that.