It's bad enough that the entrance chamber, which slopes down about 150 feet from beneath a rock face high on Mount Aeolus, is called "Guano Hall," but far worse is the smell of the estimated 10,000 to 20,000 dead bats decomposing on the chamber's floor.
Luckily, I hadn't eaten all day, and right then, I was quite sure I wouldn't be hungry again for some time.
"It's like a scene from a zombie movie, isn't it?" said Jon Reichard, a Boston University doctoral student who's trying to find a cause for white-nose syndrome, a mysterious disease that has been devastating bat populations in the Northeast for two years.
Actually, to be honest with him, I didn't know. The light near the cave's iron gate, meant to keep out spelunkers, had quickly faded to black, and I was having enough trouble traversing down the icy cave floor, about as steep as a black-diamond trail, in my large rubber boots and white protective suit.
"Um, John, your light's not on," a voice said behind me.
OK, I may not be an expert spelunker, or one at all, but once I turned it on (with a little help), I saw exactly what he was talking about.
The dirt I had been feeling underneath my feet and occasionally on my latex gloves, if I slipped, turned out to be decomposing bats, covered in fungus (not from white-nose), that could only be described as "mushy.
For me, the scene was disturbing (I actually did develop a fondness for bats during the trip). However, for wildlife biologists or conservationists, like David McDevitt, the scene, and many others like it, is far more tragic.
"It's as bad as anything I've ever seen in my life," said McDevitt, one of my tour guides on March 27 and a southern Vermont land steward with the Nature Conservancy, of the syndrome. " ... I knew someone who worked on the Exxon Valdez (oil spill), and he said that paled in comparison to this."
Aeolus Cave, owned by the Nature Conservancy, is home to the most hibernating bats in New England each year or, at least, it used to be.
Bats had been hibernating at Aeolus, which is also believed to be the longest cave in New England at 3,000 feet, without incident for more than 10,000 years, according to Scott Darling, a bat biologist at the Vermont Fish and Wildlife Department. That was until last winter, when the syndrome, first found in New York two years ago, was discovered in Vermont.
Now, the syndrome, with about a 90 percent mortality rate, has spread to nine eastern states and affected upwards of 1 million bats. In Vermont alone, Darling recently pegged the number of diseased bats between 400,000 and 500,000.
He said it has been discouraging to watch it spread. The feeling of helplessness has sometimes been overwhelming.
"Each biologist feels for the well-being of the species that he or she tries to protect," Darling said Wednesday, "so to have this happen on, what I considered to be, my watch has been a particular blow."
Although scientists have identified a new species of fungus, which might be linked to the disease, they still have not found a cause or cure.
That's what Reichard, along with Marianne Moore, also a doctoral student, and Tim Murtha, a recent graduate, are working on, along with a number of other universities and organizations.
The team from Boston University is testing various bats to find signs that could help separate sick bats from healthy ones. So far, their results are too preliminary to report.
McDevitt said he will always remember a trip to Aeolus, when a bat, on the rock face above the cave's entrance, fell head first into the snow.
"Only its feet were sticking out," he said, "and it died there, right in front of me."
On my trip, a lone, trembling bat, trying to stay warm, clung to a sunny rock face outside the cave's gate.
The bat, and the others periodically flying out between the gate's thick bars, should have been hibernating deep inside the cave in late March. However, scientists believe a skin irritation, associated with the syndrome, causes bats to wake early, depleting them of their fat reserves and, ultimately, killing them.
"This guy doesn't stand a chance," McDevitt said.
Signs of past meals were all around him, scavenger droppings and small piles of shriveled bat wings.
He would likely soon be consumed, the latest causality of white-nose syndrome, but far from the last.
Contact John D. Waller at firstname.lastname@example.org