Since no one else has decided to tackle this, I figured I would give it a try. By RAW, they don't need the Track feat to track enemies. That's clear. Determining what an enemy is, by RAW, would almost certainly use the same rules as determining an 'enemy' for a spell...which...does not...seem...to have a clear RAW definition in the SRD.
Hrm.
Okay, moving on (and ignoring that little inconsistency), I would still rule 'enemy' as having the same definition as for spells, whatever that happens to be.
*cough*
The point! Yes. The point. That I was going to make. --Was that I noticed in reviewing the minotaur that survival is not listed as a class skill for minotaurs, and they get no bonuses to survival whatsoever, either through a wis boost or a skill bonus. They also get a whopping -4 (!!!) to intelligence, which means that they are usually going to get 1 skill point per level, and rarely more than 2.
Keeping all that in mind, I hardly think it's overpowered to allow minotaurs to track enemies. Even if they take a class like ranger/druid (ha!!!)/barbarian, they still have 'wasted' 8 levels where survival was not a class skill, and are unlikely to catch up soon. In short, their survival check is probably going to suck anyways, and RAW is unclear, so why not give it to them?
Heck, just to avoid arguments over what exactly defines an "enemy", I'd probably give them Track anyways; it's hardly unbalancing imo and good flavour. Helps keep the minotaur from being a complete "KROK FIGHT!!!" type of character.