Since the 1890s, we've been building machines that wait in our place, in the dark, for something to move. This is the story of how a thread across a trail became a sensor that can feel heat, and what we learn when we really look.
In this Episode
- George Shiras: the Michigan naturalist and early wildlife photographer who rigged the first trip-wire camera traps in the 1890s
- Pyroelectricity: the physical property that lets a crystal generate a faint electrical charge when its temperature changes
- The Fresnel lens: how a design borrowed from 19th-century lighthouses now focuses invisible infrared light onto motion sensors in camera traps, driveway floodlights, and burglar alarms
- The Haíɫzaqv Nation's coastal wolfs: How a camera trap on the coast caught a wolf doing something scientists didn't know wild wolves were capable of
- Machine learning classifiers: how citizen scientists trains algorithms to sort real animal sightings from the false alarms
- Colorado's gray wolf reintroduction: the closely monitored 2023 reintroduction effort and recent events
Episode Music
Additional Reading
Cecco, L. (2025, November 20). Raiders of the lobster pot: Wily wolves learn to haul in Canadian crab traps. The Guardian. https://www.theguardian.com/world/2025/nov/20/canadia-british-coumbia-sea-wolves-learn-to-loot-crab-traps-for-bait
Davenport, J. (2025, August 31). Wolf encounters & insights: 2025 newsletter. Churchill Wild. https://churchillwild.com/wolf-encounters-insights-2025-newsletter-by-jad-davenport/
Keller, H. J. (2000, May 11). 30 years of passive infrared motion detectors: A technology review [Paper presentation]. OPTO/IRS2, Erfurt, Germany. https://jvs.de/Carclo_Fresnel/pdf_content/2000-05_irs2paper_Hans_j_Keller.pdf
Longwell, A. (2025, July 17). WATCH: Colorado Parks and Wildlife shares first footage of state's newest wolf pups. Vail Daily. https://www.vaildaily.com/news/colorado-wolf-pup-video-routt-county/
Ross, T. (2026, August 10). Colorado hunter thought wolf shot and killed in January was a coyote. The Colorado Sun. https://coloradosun.com/2026/08/10/colorado-hunter-kills-wolf-thinking-it-coyote/
Shiras, G., III. (1906, July). Photographing wild game with flashlight and camera. The National Geographic Magazine, 17(7), 367–423.
Shiras, G., III. (1908, June). One season's game-bag with the camera. The National Geographic Magazine, 19(6).
Shiras, G., III. (1935). Hunting wild life with camera and flashlight: A record of sixty-five years' visits to the woods and waters of North America (Vols. 1–2). National Geographic Society. https://archive.org/details/HuntingWildLifeWithCameraAndFlashlight.Volume121935Copy
Slade, R. (2026, June 4). The outdoorsman who made wildlife photography a big deal for National Geographic. National Geographic. https://www.nationalgeographic.com/history/article/george-shiras-iii-wildlife-photography
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