Why Caves Always Take the Eyes First

Cave animals don't lose their eyes because eyes are useless in the dark - they lose them because darkness turns an eye into the most expensive organ they own. Eleven animals from caves on four continents, and what the dark charged each one of them: a spider family new to science whose diet nobody has worked out, the deepest land animal ever recorded, a bacterium sealed in New Mexico rock for four million years that already resisted twenty-six of our antibiotics, a fish whose internal day runs forty-seven hours, and a blind salamander in Slovenia with a wild longevity estimate of a hundred and two years and no detectable signs of ageing. No folklore lane tonight - the measured numbers are stranger than the legends. Along the way one famous cave figure gets taken away as well, when mark-recapture work on three thousand eight hundred Alabama crayfish cut a hundred and seventy-six years down to twenty-two. Where studies are single, unreplicated measurements, I say so. If you liked this one, watch "13 Things Divers Found in Flooded Caves" next. #caves #wildlife #evolution Chapters: 0:00 Something in Your Hands 0:48 What the Dark Charges 1:33 11: The Hooked Spider 3:00 10: Deepest Land Animal 4:04 9: The Crayfish Correction 5:32 8: The Venomous Crustacean 7:31 7: Four-Million-Year Bacterium 9:27 6: The Sealed Ecosystem 11:32 5: A Forty-Seven Hour Day 14:15 4: Genes Gained, Not Lost 17:07 3: Eye Loss on Repeat 20:26 2: The Olm's 102 Years 23:24 1: The Real Invoice Image credits: "Postojna Cave (25770646640)" by Amanda Slater from Coventry, West Midlands, UK, CC BY-SA 2.0 - https://commons.wikimedia.org/wiki/Fi... "ZooKeys-215-077-g001 Trogloraptor marchingtoni" by Griswold, Charles; Audisio, Tracy; Ledford, Joel, CC BY 3.0 - https://commons.wikimedia.org/wiki/Fi... "Plutomurus ortobalaganensis 1980m" by Enrique Baquero Link to Wikispecies, CC BY-SA 3.0 - https://commons.wikimedia.org/wiki/Fi... "Speleonectes tulumensis (10.7717-peerj.2305) Figure 1 (cropp" by Ivanenko VN, Antonenko EA, Gelfand MS, Yager J, Ferrari FD. 2016. Changes in seg..., CC BY 4.0 - https://commons.wikimedia.org/wiki/Fi... "Lechuguilla Chandelier Ballroom" by Dave Bunnell / Under Earth Images, CC BY-SA 2.5 - https://commons.wikimedia.org/wiki/Fi... "Movile Cave schematic illustration" by Kristmac, CC BY-SA 4.0 - https://commons.wikimedia.org/wiki/Fi... "Cyprinidae - Phreatichthys andruzzii" by Hectonichus, CC BY-SA 3.0 - https://commons.wikimedia.org/wiki/Fi... "Leptodirus hochenwartii" by Yerpo, CC BY-SA 3.0 - https://commons.wikimedia.org/wiki/Fi... "Astyanax mexicanus (10.3897-subtbiol.73.79318) Figure 2" by Espinasa L, Collins E, Ornelas García CP, Rétaux S, Rohner N, Rutkowski J (2022), CC BY 4.0 - https://commons.wikimedia.org/wiki/Fi... "Lascaux 015" by JoJan, CC BY 4.0 - https://commons.wikimedia.org/wiki/Fi... "Olm (Proteus anguinus) in Moulis, Ariege (Laboratoire souter" by Javier Ábalos Alvarez from Madrid, España, CC BY-SA 2.0 - https://commons.wikimedia.org/wiki/Fi... "Pachón cave (10.3897-subtbiol.21.11046) Figure 2" by Espinasa L, Bonaroti N, Wong J, Pottin K, Queinnec E, Rétaux S (2017) Contrastin..., CC BY 4.0 - https://commons.wikimedia.org/wiki/Fi... "Proteus anguinus in postojna cave IMG 7977" by Bjoertvedt, CC BY-SA 4.0 - https://commons.wikimedia.org/wiki/Fi...