In the Yahweh temple in Jerusalem, Yahweh was worshipped as a cult statue in the form of a costly donkey bust. Josephus writes:
“In the temple in Jerusalem, as Apion impudently asserts, the Jews set up a donkey’s head; they pray to it and address their entire worship to it (CA II, 7). Tacitus reports that the Jews set up the holy image of a donkey in the Holy of Holies in their temple (Histories V, 4).
The same accusation was made against the Christians in the 3rd century AD: Minicius Felix writes in his dialogue Octavian (28, 7) that the Christians consecrated a donkey’s head. A well-known caricature from the 2nd/3rd century AD on the Palatine (now Rome, Antiquarium Palatin Inv. 381403) shows a soldier standing below a crucified man with a donkey’s head. The inscription reads: Alexaminos praying to his god.
The Gospels describe Jesus riding into Jerusalem on a donkey colt, cheered by the crowd: Matt. 21:1ff; cf. Zech. 9:9. In the Old Testament, the prophet Balaam rides on a donkey mare with visionary powers: Num. 22:23ff. Since animal gods were worshipped all over the Middle East, the principle of the simplest explanation (Occam’s razor) makes it very plausible that the Jews did the same.