The Jaredite prophets were sent to warn the people just as the Nephite prophets had been sent to warn them (v. 28; cp. Mosiah 11:20; Alma 9:1; 3 Nephi 6:20). The Lord sent a famine among the Jaredites (Ether 9:28–30). Nephi, son of Helaman, called a famine upon his people just prior to the birth of Christ (see Helaman 11:5–6). The poisonous serpents that came upon the Jaredites (Ether 9:31–32) do not have a Nephite parallel, but it does have a biblical parallel. Moses and the Israelites encountered serpents sent by the Lord as they traveled to the land of Edom.
4 And they journeyed from mount Hor by the way of the Red sea, to compass the land of Edom: and the soul of the people was much discouraged because of the way.
5 And the people spake against God, and against Moses, Wherefore have ye brought us up out of Egypt to die in the wilderness? for there is no bread, neither is there any water; and our soul loatheth this light bread.
6 And the Lord sent fiery serpents among the people, and they bit the people; and much people of Israel died.
7 Therefore the people came to Moses, and said, We have sinned, for we have spoken against the Lord, and against thee; pray unto the Lord, that he take away the serpents from us. And Moses prayed for the people.
8 And the Lord said unto Moses, Make thee a fiery serpent, and set it upon a pole: and it shall come to pass, that every one that is bitten, when he looketh upon it, shall live.
9 And Moses made a serpent of brass, and put it upon a pole, and it came to pass, that if a serpent had bitten any man, when he beheld the serpent of brass, he lived. [Numbers 21:4–9]
Nephi, son of Lehi, confirms the Bible account and taught his people the symbolism of Christ in the Moses incident:
And he did straiten them in the wilderness with his rod; for they hardened their hearts, even as ye have; and the Lord straitened them because of their iniquity. He sent fiery flying serpents among them; and after they were bitten he prepared a way that they might be healed; and the labor which they had to perform was to look; and because of the simpleness of the way, or the easiness of it, there were many who perished. [1 Nephi 17:41]
While most people have not experienced swarms of serpents and must accept the Jaredite and Moses accounts by faith, Dr. Hugh Nibley gives support to that faith.
The description of how people were driven out of a land by a plague of serpents that then “hedge up the way that the people could not pass” (Ether 9:31–35) may put a strain on your scientific credulity. I hasten to relieve it. Pompey the Great, we are told, could not get his army into Hyrcania because the way was barred by snakes along the Araxes, a stream that still swarms with the creatures. One of the chief philanthropic activities of the Persian magi was to make war on the snakes—a duty which must go back to a time when the race was sorely pressed by them. The Absurtitani were said to have been driven from their country by snakes (Hyginus #26), and Esarhaddon of Assyria recalls the horror and danger of a march by his army through a land “of serpents and scorpions, with which the plain was covered as with ants.” In the thirteenth century A.D. Shah Sadrudin set his heart on the building of a capital which should surpass all other cities in splendor; yet the project had to be abandoned after enormous expense when during a period of drought the place so swarmed with serpents that no one could live in it. It is interesting in this connection that the plague of serpents in Ether is described as following upon a period of extreme drought.
The people devouring the carcasses of beasts slain by serpents (Ether 9:34) shows the severity of the famine. The famine was abated when the Jaredites finally humbled themselves before the Lord (v. 35). The same was true with the Nephites famine cited above (Helaman 11:7–17). The Lord offered the same solution to the children through Moses (see Numbers 21:10–17).