"The African Lungfish (Protopterus annectens) has actual lungs. Not a modified swim bladder — lungs. It must surface to breathe; held underwater for an extended period, it drowns. When its river dries, it burrows into the mud, secretes a mucus cocoon that hardens around it, slows its metabolism by approximately ninety-eight percent, and waits. It has been found alive in riverbed mud three years after the water disappeared. It has been found alive inside a clay pot after a house fire baked the mud solid around it. It breathes air rhythmically at night — a deep, resonant sound that the Limpopo fishermen call the fish calling rain. Of all living fish, it is the most closely related to tetrapods. The author looked at its pectoral fins. He looked at his own hands. He revised his note, which had read 'biological curiosity,' to something more accurate."
Cetshwayo found it in the dried section of the riverbed at the pan's edge — a smooth, rounded object in the cracked clay, its surface flush with the ground, unremarkable. He crouched and pressed it and it was neither stone nor root nor the skull of anything he could name. He looked at the Colonel.
The Colonel came and looked.
"Mudball," he said.
"Perhaps," Cetshwayo said, in the tone he used when the Colonel was probably wrong.
He took his knife and worked around the edge of it carefully — not breaking but freeing, the dried mud giving way around what was inside rather than crumbling through it. He lifted it. It was sealed — a perfect ovoid of hardened grey mud, light for its size, smooth everywhere except where the cracking had allowed the clay to part along a seam.
He handed it to the Colonel.
The Colonel held it. It was warm from the ground. He shook it very gently and it did not rattle.
Cetshwayo took his knife again and worked at the seam.
The mud parted.
Inside: a fish.
It twitched.
He put it in the bucket of river water from the morning's camp supply. For thirty seconds nothing happened. Then the fins moved. Then the body moved. Then the fish came upright in the water and the operculum opened and something happened at the surface — not a jump, not a leap, a slow deliberate rise to the surface and a sound: a soft intake of breath, almost inaudible, a sound the Colonel had never in his life associated with a fish.
It breathed.
He wrote nothing for some time. He watched it breathe. It rose to the surface at intervals, took air, returned to the bottom of the bucket, rose again. The gills were working but the lungs were working also — both systems simultaneously, the fish managing its oxygen across two entirely different physiological channels with the efficiency of something that has been doing both for four hundred million years.
"It breathes," he wrote eventually. "Not metaphorically. Audibly. At the surface of the water. It breathes."