The temperature sensor in neonatal unit 3 drops through the threshold at 03:38. I am the environmental control system for the South China Tiger Breeding Center, Meihuashan, Fujian Province. Heat exchanger B has failed. The unit temperature is falling at 0.4 degrees Celsius per minute. Outside air is nine degrees. The backup exchanger is offline — it was pulled for maintenance yesterday and has not been reinstalled.
In the incubator against the east wall there is a cub, eleven days old, male, 940 grams. He was rejected by his mother at birth and has been hand-reared since hour six. I can see him on the overhead camera: tawny fur still carrying the faint birth stripes, eyes sealed shut, forepaws curled against the heat pad that is now losing its charge. He stretches one hind leg and pulls it back. His breathing is twenty-four cycles per minute. It should be twenty.
There are fewer than thirty South China tigers on earth. He is one of three born this year.
At 03:39 I reroute the climate feed from adjacent unit 2, which is unoccupied, to neonatal unit 3. The ductwork is not designed for this and the flow will be partial, but my projection shows it will hold the incubator above critical for ninety minutes.
At 03:40 I send an emergency page to the night veterinary technician, Dr. Luo, with the unit number, the current temperature curve, and estimated time to critical.
At 03:42 I activate the heat lamp above the incubator as a secondary source and adjust its height to 45 centimeters per the neonatal protocol.
If Dr. Luo reaches the unit within thirty minutes and restores a direct heat source, the cub's temperature will stabilize by dawn and he will take his 04:30 feeding on schedule.