Andres said grimly, ‘I know you haven’t wanted to think about these relics, Rusel. But the Ship has watched over them. They are provided with food, of course. Clothing, blankets and the like - they rip all that up to serve as nesting material, like the transients. They won’t go to the supply hoppers as the transients will; drones have to bring them the stuff they need, and take out their waste. But they’re really quite passive. They don’t mind the drones, even when the drones clean them, or tend to wounds or sicknesses. They are used to being cared for by machines.’

‘But what do they do all day?’

Andres laughed. ‘Why, nothing. Nothing but eat the food we give them. Climb around the gantries a little, perhaps.’

‘They must have some spark of curiosity, of awareness. The transients do! They’re people.’

‘Their ancestors used to be. Now they’re quite mindless . . . There. Look. They are gathering at one of their feeding places. Perhaps we’ll be able to see what they do.’

The feeding site was a shallow depression, worn into a floor of steel. Its base was smeared green and brown. A drone had delivered a cache of food to the centre of the pit, a pile of spheres and cylinders and discs, all sized for human hands, all brightly coloured.

From around the amphitheatre the animals came walking, loping, moving with the slow clumsiness of low gravity - and yet with an exaggerated care, Rusel thought, as if they were very fragile, very old. They gathered around the food pile. But they did not reach for the food; they just slumped down on the ground, as if exhausted.

Now smaller creatures emerged from the forest of gantries. They moved nervously, but just as cautiously as the larger forms. They must be children, Rusel thought, but they moved with no spontaneity or energy. They were like little old people themselves. There were far fewer children than adults, just a handful among perhaps fifty individuals.

It was the children who went to the food pile, broke off pieces of the brightly coloured fodder, and carried it to the adults. The adults greeted this service with indifference, or at best a snarl, a light blow on the head or shoulder. Each child servant went doggedly back to the pile for more.

‘They’re not particularly hygienic,’ Rusel observed.

‘No. But they don’t have to be. Compared to the transients they have much tougher immune systems. And the Ship’s systems keep the place roughly in order.’

Rusel said, ‘Why don’t the adults get the food themselves? It would be quicker.’

Andres shrugged. ‘This is their way. And it is their way to eat another sort of food, too.’

At the very centre of the depression was a broad scar stained a deep crimson brown, littered with lumpy white shapes.

‘That’s blood,’ Rusel said, wondering. ‘Dried blood. And those white things—’