Man, can you imagine how hard it must have been to keep all those animals from eating? The Mesopotamians kept sheep, goats, pigs, oxen, horses, donkeys, and camels -- all grazing animals, except for pigs, who, like goats, will just eat any damn thing they find. How do you even fast a goat? You'd have to tie it up on a really short rope, so it couldn't just eat the rope. And tie the other end to a rock or something. That's to say nothing of putting sackcloth on all those animals. I mean, one doesn't have just one sheep, one has a herd of sheep. How much sackcloth did your average Ninevite have? I hope this is a deliberately humorous idea, because it's certainly funny to me.
Now, the life of your average Biblical Middle Easterner involved a lot more contact with animals than the life of your average modern American, but even with that taken into consideration, the Book of Jonah devotes a lot of time to animals. Jonah has an animal name, and he gets swallowed by an animal, and there is serious concern about the fate of the livestock in Nineveh, and there's an incident with a worm in the next (and last) chapter that really brings it all home. In fact, the livestock literally get the last word. It's part of the book's emphasis on the natural world in general, and humanity's various relationships to it: there's a tremendous storm that threatens the ship, and a whale that swallows a man and a gourd that shelters him (oh man, wait until we get to the gourd), and a "vehement east wind" that knocks over a tent, and so on. Jonah's prayer within the fish is couched in terms of submission to the natural world and thus to God, who controls it: "For thou hadst cast me into the deep, in the midst of the seas; and the floods compassed me about: all thy billows and thy waves passed over me.... The waters compassed me about, even to the soul: the depth closed me round about, the weeds were wrapped about my head." So sure, it's funny that the animals are involved in Nineveh's repentance, but at the same time it makes perfect sense: the natural world, the world of earth, wind, water, and animals, is a terrifying one that is controlled by God and can only be survived with his help; if you piss God off, he will relinquish this help, and it is by the untamed forces of nature that you will be punished. So you want to keep a close eye on the ways in which you interact with nature. Remember how careful the sailors were about making sacrifices and vows to a foreign god, once they had witnessed his power over nature? At that point Jonah had already gone overboard, and you'd expect the narrative to follow him immediately, this being something of an action sequence; the emphasis on peripheral characters stands out. All human interactions with nature are underlined like this in the Book of Jonah. So we've seen how humans deal with being in the midst of nature; now we're seeing the reverse, how humans deal with the natural world in their own midst. Wisely, they deal with it by using it to emphasize their submission to the god that controls it: they put sackcloth on their livestock. Hilarious, but at the same time pretty brilliant. Don't wait for God to use nature to smash you: forestall him by using that very same nature to demonstrate why he shouldn't! Man, no wonder that guy is king, that's a masterful stroke. That's sticking a flower in the barrel of the tank gun.
Here ends chapter three; only the eleven verses of chapter four remain. Delightfully, in them God talks to Jonah pretty much as I've heard my sister talk to Aglet when he gets into a sulk. "Then said the Lord, Doest thou well to be angry?"