The Weirdest Thing I Learned This Week · Popular Science

Vintage Antivaxxers, Horror Flick Psychology, Robin-Eating Bats

December 3, 2025·57 min·5 clips

Scientists captured the first-ever recording of a tiny European bat hunting and devouring a robin mid-flight at 4,000 feet.

The episode begins with Sarah Kiley Watson sharing fascinating bat facts, including that Mexican free-tailed bats are the fastest mammals on Earth at 100 mph and that bat guano was once Texas's biggest mineral export before oil. The main story focuses on the greater noctule bat, Europe's largest bat species, which scientists discovered hunts birds despite being only 50 grams. Using sensor backpacks, researchers captured audio of a female bat climbing 4,000 feet to attack a robin mid-flight, then spending 23 minutes eating it while flying. The recording reveals the bat bites off the bird's wings and uses its leg membrane as a pouch for in-flight dining. This behavior helps explain how these threatened bats survive in fragmented habitats affected by climate change and deforestation. Rachel Feltman then explores the first anti-vaccine movement from the late 1700s, which emerged after Edward Jenner developed smallpox vaccination using cowpox from milkmaids. Opposition included vivid propaganda cartoons showing people transforming into cows and babies being fed to demonic cattle. Key opponent William Rowley had financial motivations, as he profited from dangerous traditional smallpox inoculation procedures. The movement gained momentum when England made vaccination compulsory with fines for non-compliance, creating a class-based system where wealthy people could ignore mandates while poor families faced financial ruin. Anti-vaccine pamphlets claimed children would develop bovine characteristics or become mentally impaired. The historical context reveals that free vaccination programs for the poor were often unsanitary and dangerous, performed by untrained people with dirty instruments in public spaces. Despite legitimate safety concerns about implementation, smallpox vaccination ultimately succeeded in eradicating the disease by 1980. The episode highlights parallels between historical and modern vaccine hesitancy, including financial motivations behind opposition, class-based enforcement issues, and the challenge of discussing rare but real vaccine risks. Both stories demonstrate how survival - whether for bats adapting to habitat loss or humans confronting deadly diseases - involves complex trade-offs and unintended consequences that persist across different eras.

As heard by us

A playful tour of fear, immunity, and why weird facts stick.

This episode uses odd facts to open a bigger question: how people make sense of danger, history, and plain curiosity. The vaccination section carries the most weight.

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Why you'd press play

You want one funny detour from cowpox to morbid curiosity and scary play here.

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