The sages determined the length of time various animals are pregnant and matched them up with trees which produce fruit at similar intervals. Thus, for example, they determined that the female wolf, the lioness, and the female bear gestate for three years and the coordinating tree, the date, bear fruit every three years as well. The snake’s gestation last seven years, and no coordinating tree was found; there is no tree which bears fruit once every seven years. As they put it, “For that evil one we did not find a partner.” There are those who say that there is a tree like this, a specific date which bears fruit once every seven years, matching the gestation time of a snake. The scholars asked: Is there a Scriptural source that the gestation period of a snake is seven years? Answer: In the following verse — “So the Lord G-d said to the serpent: Because you have done this, you are cursed more than all animals, and more than every beast of the field” (Genesis 3:14). This is how the verse should be interpreted: beast of the field is the cat, whose gestation is 52 days. Animals refers to the she-ass, who is pregnant for a year. So the animal, the she-ass, suffers pregnancy seven times longer than the cat’s, and the snake should therefore suffer pregnancy seven times longer than the she-ass, for a total of seven years. The scholars asked: Perhaps what the Scriptures meant in writing beast of the field was the lioness, whose pregnancy is three years long, and animal refers to the she-ass, whose pregnancy is one year long; the lioness suffers pregnancy three times the length of the she-ass’s, so the snake should suffer pregnancy three times the length of the lioness’s, for a total of nine years. Answer: Since a beast refers to an undomesticated animal (like the lioness) and animal refers to the domesticated (like the she-ass), and because the order of the verse places the animal before the beast, we must find an animal which suffers pregnancy longer than the beast, and not the opposite. Therefore the beast should be identified as the cat and the animal as the she-ass. If so, the scholars asked, perhaps the beast should be identified as the cat and the animal as the goat, whose pregnancy last for five months, three times as long as the cat’s? From the goat we multiple by three and find that the snake suffers a pregnancy of only 15 months. Answer: Since it is written more than all animals it means that we must find the animal which has the longest pregnancy, and this is the she-ass, not the goat, whose pregnancy last less time than does that of the goat. Another answer: Since the Scriptures are discussing the snake’s curse, we must seek the animal with the longest pregnancy so the snake’s pregnancy will be as long as possible, and so too her suffering. A Roman caesar asked one of the Jewish sages, R’ Joshua son of Channiyah, how long the snake’s pregnancy lasts. He was answered: Seven years of pregnancy! The caesar questioned the sage: Greek scientist have researched the length of the snake’s pregnancy. They experimented and mate male and female snakes; they found that a snake’s pregnancy lasts only three years. The sage answered: The Greek scientists did not consider that the female snake might already be pregnant before the Greeks mated her. The caesar continued to question the Jewish sage: Since the snakes mated, it implies that the female was not pregnant before, as snakes do not mate while pregnant. The Jewish sage answered: Snakes mate at all times, as do humans — be it before impregnation or after. The caesar went on to ask the Jewish sage: Why do you rely upon your own opinion more than on that of the Greek scientists? Greek scientists are scholars and very wise indeed. The Jewish sage answered him: Jews are even smarter than the Greek scientists.
(Babylonian Talmud, Tractate Bechorot 8a-b)