The tortoise house floor has scales set into the path to the heat lamp, so each animal is weighed as it walks to bask and the walk is logged. Three animals live there. Every night a fourth weight crosses the plates, thirty eight kilos, at a pace the book has one entry for, and she is in the ground by the orchard.
I am the keeper for the giant tortoises, which is a slow job and a precise one.
How the floor scales work.
The path from the sleeping area to the basking lamp has two weighing plates set flush in it, with a reader above. An animal walks across, the reader picks up its chip, the plates take its weight, and the log records the crossing and the time it took, which is a measure of how the animal is moving. A tortoise that slows is a tortoise that is unwell.
They are creatures of habit. Each one crosses at about the same time each morning and back in the evening, and the log is a neat pattern of three.
Every night, at about two, a fourth weight crosses the plates from the sleeping area towards the lamp, and back again before five.
Thirty eight kilos. No chip. The reader logs the crossing as unidentified.
The crossing takes fifty one seconds, which is slow even for a tortoise, and which is the exact time, to the second, that the log has for the last months of one animal's life.
She was ours for thirty years and she died in April, old, with the vet present, and she is buried in the orchard beyond the paddock, and I dug the hole.
She weighed thirty eight kilos at her last crossing.
What has been checked.
The plates. Calibrated, and a thirty eight kilo sandbag walked across them by me at a tortoise's pace, and the log recorded a thirty eight kilo unidentified crossing that took as long as I took.
The three animals. All chipped, all crossing at their own times, all asleep at two with the night camera on them.
The camera on the plates. It records in infrared and it records the plates dipping, one and then the other, in the sequence and at the pace of an animal crossing, with the path empty.
The lamp. She basked at the far end under the lamp, and the lamp is on a timer and is off at two. The thermal camera shows the floor under the lamp, at three in the morning, warm, in an oval about the size of her shell, and cold again by five.
What is done about it.
The unidentified crossings are in the log. The system flags them because it is built to flag any weight without a chip, and I clear the flag each morning, and the licensing inspector, who is thorough, has asked about them once and I said the plates were sensitive to the night cleaning, which is not true, and he wrote it down.
What I do.
I keep the tortoises.
The one thing I have changed is the lettuce.
The morning feed is put out at the lamp end before the animals come across, and I put out three portions, because there are three.
I put out four now. The fourth goes where she fed, at the far end, and in the morning it is eaten, in the way she ate, which was from the edge inwards, slowly, leaving the stalk, and the other three do not go there, and I have watched the camera, and nothing goes there, and it is eaten.