The hydrus and the crocodile: a struggle that tells of the descent into hell
In the bestiaries the hydrus coats itself in mud, lets the crocodile swallow it and bursts out of its belly: a figure of Christ conquering death.
The crocodile, a beast of the Nile that few medieval Europeans had seen, was well represented in the bestiaries, and almost always accompanied by its most fearsome enemy: the hydrus, a small water creature able to kill it from the inside. Their struggle, already described in the Physiologus, became one of the most effective images of Christ’s descent into hell. Following the story of this pair also means seeing how ancient reports about Egypt merged with Christian theology.
The crocodile of the ancients
Herodotus, in the second book of his Histories, devoted to Egypt, had already described the crocodile in great detail: it lays its eggs on dry land, spends the night in the water, and is the only animal that moves its upper jaw rather than its lower one. The Greek historian also tells of the small bird that is said to enter the reptile’s open mouth to clean its teeth. These reports, taken up by Pliny and then by Isidore, passed into the bestiaries.
Isidore of Seville, in the Etymologies, places the crocodile among the fish, because it lives in water, and explains its name by the saffron-yellow colour, crocus in Latin, of the animal. According to this entirely unfounded Isidorian etymology, the crocodillus would be named a croceo colore. The illuminators, who had no direct models, often painted it as a kind of dragon or large lizard with dog-like legs.
The enemy that enters the mouth
The hydrus, also called enhydris, is described as a serpent or water creature, the deadly enemy of the crocodile. When it sees the reptile asleep on the bank with its mouth open, it rolls in mud to make itself slippery, then enters its jaws. The crocodile, waking, swallows it. But the hydrus, still alive, tears through its entrails and comes out of its body, leaving it dead.
The bestiaries’ interpretation is clear. The crocodile is hell, or death, which devours human beings. The hydrus is Christ, who clothes himself in human flesh as the hydrus covers itself in mud, and descends into hell. There he breaks the power of death, frees the souls of the righteous and comes out victorious. The theme of the descent into hell, also told in the apocryphal Gospel of Nicodemus, was very dear to medieval art.
Hypocrites and tears
The crocodile was also given another, more moral reading. Some bestiaries describe it as an image of hypocrites and the lustful, who by day appear virtuous and by night give themselves up to pleasure, like the reptile that lives between land and water. The animal’s double nature, amphibious and deceptive, lent itself well to denouncing those who lead a double life.
From this tradition comes a saying that is still alive. In the late Middle Ages the belief spread that the crocodile weeps while devouring its victim, and we find it for example in the Travels attributed to John Mandeville. ‘Crocodile tears’ thus became the symbol of false repentance, displayed by someone who has just done evil and has no intention of giving it up.
The pair of the hydrus and the crocodile shows the ingenuity with which the Physiologus built its allegories. A violent tale of natural history, perhaps born from distorted observations of the fauna of the Nile, became the vehicle of a truth of faith: death itself, which seems to swallow everything, can be defeated from within by one who has agreed to enter it.