Is there any way to get wild empathy without dipping Druid or Ranger? A class that can use Charisma would be preferred for optimal diplomacy.
A bard with the Animal Speaker archetype sounds like what you're looking for. At level three they can perform to wild empathy. The archetype doesn't lose anything amazing either.
A few prestige classes offer it as well. Mammoth Rider, Field Agent, Green Faith Acolyte. Not ideal in the least however. There's always the spells Charm Animal & Dominate Animal. These need wands b/c of the spell lists they're on, but they're options. Oh, witches have a hex that does something similar as well: Charm. Rather weak however. . . certain domains & the like can grant Charm Animal as well.