When you find wolves, they despawn quickly and never respawn. If you are lucky enough to tame on and it turns into a dog, it despawns as well. They never respawn. Total life span once they are found seems to be around 1 minute
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Duplicate of MC-28424. Unless this is a more extreme version of that.
Nick, why would untamed wolves be despawned intentionally? Non-hostile (farm animals, horses, etc.) mobs never despawn period.

Yeah, this is not a duplicate. This happens standing in the same chunk, staring right at them, and as metioned even the tame one despawns. I would expect them to despaw nif I wandered off for some time and then came back as described i that report. This is not that

This may be a duplicate of MC-65040.
Is this still an issue in Minecraft 1.8 ?
That's my understanding, but they do. They just fixed a similar issue regarding slimes that popped up again, so we'll see if that fixes this problem too