Favored animal

A favored animal was a minor manifestation of a deity.

Description
Deities could show their powers through major manifestations and minor manifestations. The appearance of an animal (or plant) fell into the latter category.

Most deities had some kind of mundane animal as their favored animal. Some deities were specific in the coloration of their favored animals. For example, Vhaeraun had black cats and not all cats as his favored animal.

Real or illusory specimen of these animals were sent by deities to inform mortals on something. For example, Lolth sent her favored animals, spiders, to show her approval for the conclusion of a ritual. These animals could be made to act according to their normal behavior or in some strange manner by the sending deity.

The background for using animals as an omen was that it was easier for mortals to befriend and get used to animals than the more monstrous servants of a deity.

Mortals' Reaction
When a real specimen of a favored animal appeared, it was usually captured. What happened with it afterwards was dependant on how wealthy the capturing community was. If it was rich, the animal was given a pampered easy life to show the community's devotion to the deity. If the community was poor, the animal was eaten and the best parts of it were sacrificed to the deity.

Clerics often summoned fiendish or celestial versions of these animals.