Question about animals

[Arsenic]

In my current play through I managed to find a herd of reindeer sitting on a hill. I threw my spear at one and managed to hit its hind leg but did not manage to get the kill before needing to sleep.

My question is; is there any chance that ill find this specific reindeer, and have a shot at getting my spear back? or did it despawn completely because I slept?

[LoLotov]

It won't despawn over night, and will probably be within two or three tiles of you. Better yet, you'll be able to find the exact one currently "carrying" your javelin by using the look command. The look command should also give you a good idea of how severe the injury you dealt it is, so you can adjust your pursuit based on how difficult it will be to catch.