Something's rotten at the original "Tiger King" zoo, now owned by Jeff Lowe -- 2 cadaver dogs have zeroed in on what their trainer believes are human remains ... TMZ has learned. We're told the dogs were brought in as part of an episode of Zak Bagans' "Ghost Adventures." Our sources say the dogs picked up the scent Thursday ... in the alligator pit. The local sheriff's deputies are on the scene right now, and we're told they're currently discussing a method to determine if remains are there ... and, if so, how to dig them up safely. The zoo, in Wynnewood, Oklahoma, was originally Joe Exotic's baby ... before he partnered with Jeff, and then got convicted in federal court for solicitation of murder and various animal abuse charges. Sources connected with Joe tell TMZ ... Joe has said there are ashes of 4 people buried on the property as a memorial -- people who chose to make the zoo their final resting place. The sources did not identify who was buried there. Story developing ...