Conger

You shine your light into a fissure and a large head appears in the beam. The conger barely moves. Its body remains hidden in the rock, as is often the case during the day.

It is difficult to imagine that an animal so massive could one day undergo a radical transformation. Yet a wild female captured in the Tyrrhenian Sea after spawning allowed researchers to observe what can happen at the end of this cycle.

Her body had drawn deeply on its own reserves for reproduction. X-rays revealed severe decalcification of her skeleton and, more surprisingly still, the loss of her teeth.

This case does not prove that all females undergo exactly the same transformation, but it shows how far the conger's body can be modified after reproduction. When you encounter its massive head at the bottom of a cavity, you are therefore seeing an animal whose existence possesses a final chapter almost invisible to divers: one in which the body that allowed it to hunt and survive for years can end up being sacrificed to reproduction.

In the fissure, however, nothing suggests this. The conger simply watches you from the darkness.