User blog comment:BannedLagiacrus/Monster Appreciation Week: Emerald Congalala(4th Gen)/@comment-25119729-20151114151022/@comment-25119729-20151114171248

Could very well be. Given that Congalala farts burn in your throat, it could very well be that Congalalas don't need to hide, the gas they fart at enemies being the only thing they need to be left alone by other monsters.

On a unrelated note, I looked at the item descriptions for Emerald Congalala from 4U again and the Highrank pelt item from it has this flavor text: "New, green pelt. Grew more robust when the creature shed its purple fur." (note that this is translated, since I don't play the english version, it should be roughly the same though) This kind of confirms that Emerald Congalalas used to be normal Congalalas. It remains a mystery why it changed though.