@autopoiesis.ocean: The opening in this close-up is probably not an eye at all. The slit-shaped structure fits a spiracle, a small hole behind each eye that lets some sharks and all rays draw water in without moving.\n\nSharks lack the hard gill covers other fish use to pump water over their gills. Instead, water enters through the spiracle, travels into the buccal space and passes over the gills before leaving through the gill slits. That lets some sharks breathe while resting, and because the spiracle often sits on top of the body, an animal can keep breathing while mostly buried in sediment. The fringe around the opening likely helps keep debris out while water passes. Inside, a small pseudobranch resembles a gill but only receives blood already oxygenated by the true gills.\n\nThe dotted skin around it looks like it is covered in dermal denticles, tiny flat V-shaped scales that are more like teeth than fish scales. They are millimetre-scale, and studies disagree on how they affect swimming. One simulation found 58% more drag than a flat plate, while other work reports skin friction drag reduced by up to 30%. The species in this footage could not be identified.\n\nFollow for more! 🌊\n\n#ocean #marinelife #sharks #deepsea #Science

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Monday 02 November 2026 18:39:42 GMT