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Respiratory Anatomy
Spiracle
Spiraculum
A small opening behind the eye of many sharks and rays - the vestigial remnant of an ancestral gill slit, now used to draw water for gill respiration.
Region: Head Externally visible Unique to: cartilaginous
📖 Overview
Rays and skates, which spend time on the sea floor, cannot easily draw water through their mouths (which are pressed against sand). Instead, they inhale through their dorsally located spiracles, then expel it through the ventral gill slits.
✨ Fun Fact
A watching diver can often see rays quietly pumping water through their spiracles - a rhythmic dorsal breathing motion that mimics a small blowhole.
🔗 Related Respiratory Structures