The strange howling can be heard around Mount Chiliad and possibly around Blaine County. A video of the mystery shows a strange, periodically changing howling at the Mount Chiliad Tunnel, near the entrance of the Paleto Forest. If the player searches for the place the howling is heard from, nothing particularly interesting will be found.
It is unknown what creature makes this sound, since there are no wolves currently in the game (apart from Hunt The Beast an online game-mode.) Sometimes it is possible to hear another type of howling, but it sounds familiar as a dog yapping and players can hear it all over the Blaine County.