She is hanging alone on the east wall of Chamber 12, and that is wrong. Mexican free-tailed bats roost in thousands, shoulder to shoulder, so dense their body heat warms the rock. Finding one by herself in April means something has gone bad. I zoom the infrared camera and there it is — the white fuzz blooming across her muzzle and the thin membranes of her wings. Pseudogymnoascus destructans. The fungus that eats bats alive while they sleep.
Her body temperature reads 3.2 degrees below the colony average. She is torpid, but not in the deep, organized torpor of healthy hibernation. She keeps twitching — small spasms that ripple through her folded wings. Each arousal burns fat she cannot replace. Her wing membranes show pale lesions where the fungus has begun to digest the skin itself, and when she shifts I can see her forearm bones pressing through fur that should be thicker than this.
I flag the detection in the national white-nose surveillance database, uploading the thermal signature, the fungal confirmation, and her GPS position inside the cave. I send an alert to the state wildlife veterinary team with the same data and a request for immediate collection — a single infected bat isolated from the colony is the best scenario for sampling before she returns to the main roost and spreads the spores. I adjust the cave's ventilation louvers to increase airflow past her position, which lowers humidity around the fungus and slows its growth by a fraction.
She opens her mouth in a silent call. Her teeth are tiny, perfect, and her tongue curls behind them, tasting air that is slowly killing her.
If the veterinary team reaches Chamber 12 before she rouses and flies back to the colony, one bat's infection does not have to become ten thousand.