transfer case vent?

Yesterday I noticed a hose hanging from under my jeep. It is on the drivers side just inside the front tire. One end has a plastic hollow piece clamped in and the other end is pinned to the fenderwell under the hood with a cap on it. Where does this hose connect? I was thinking it may be the transfer case vent hose, but I have not really looked. Can anyone help so I can get on the road and to the hunting club tomorrow. Thanks. :dunno: