Marine Biologists Finally Know What's Hunting Orcas In The Pacific — And It Shouldn't Be Possible

Something is hunting the animal that has no predators. Across every ocean on Earth, killer whales are showing up with perfectly circular wounds cored out of their bodies. Clean edges. Surgical depth. Dozens of them per animal. And for decades, marine biologists looked for the culprit in the wrong direction — they looked for something bigger. The truth is the exact opposite. What leaves those marks is less than half a meter long. It fits in the palm of your hand. It has attacked orcas, great whites, dolphins, tuna, United States Navy nuclear submarines, and one long-distance swimmer crossing between Hawaii and Maui in 2009. And it does all of this using one of the most sophisticated camouflage systems in the animal kingdom — a belly that glows in the dark to erase its own silhouette, and a single dark patch behind its gills that dangles like bait attached to a predator. This is the story of the cookiecutter shark — the parasite that feeds on apex predators one bite at a time, and disappears back into a mile of darkness before its victim understands what just happened. ____________ Source used Dwyer, S. L., & Visser, I. N. (2011). *Cookie cutter shark (Isistius sp.) bites on cetaceans, with particular reference to killer whales (Orca) (Orcinus orca).* Aquatic Mammals. https://www.aquaticmammalsjournal.org/wp-content/uploads/2011/05/37_2_Dwyer.pdf Honebrink, R. R., Buch, R., Galpin, P., & Burgess, G. H. (2011). *First documented attack on a live human by a cookiecutter shark (Squaliformes, Dalatiidae: Isistius sp.).* Pacific Science. https://scholarspace.manoa.hawaii.edu/items/6a97d3dc-27d1-4f39-a01c-abc620ae86d5 Live Science. *Cookiecutter shark: The tiny shark that takes circular bites out of whales and submarines.* https://livescience.com/amp/cookiecutter-shark-weird-feeding.html Shark Angels. *Species in Focus: Cookiecutter Shark.* https://sharkangels.org/species-in-focus-cookiecutter-shark/ Souto et al. *Registros de mordidas de tubarão-charuto em cetáceos na costa da Bahia.* https://core.ac.uk/works/136363213 ____________ Music: 'Within Our Nature' by Scott Buckley – released under CC-BY 4.0. www.scottbuckley.com.au