The Atlas Obscura Podcast · Monday, August 31, 2026
Ryan Huling explained that Bracken Cave's unique thermal properties make it an ideal nursery for Mexican free-tailed bats. The sheer number of bats congregating inside the cave raises the temperature to approximately 106 degrees Fahrenheit, which is optimal for birthing and raising pups.
“For one thing, the cave's geography is really perfect for giving birth in.”
“Because the temperature inside the cave is actually slightly cooler than they need it to be for giving birth to their pups, but when you have millions of bats there, they actually increase the temperature collectively.”
“So it's because they have this huge concentration of bats there that it gets right up to about 106 degrees inside, which is the perfect temperature to give birth to a baby bat.”