09/01/2026
Grey seals can dive over 1,500 feet, holding their breath for nearly an hour at a time as they hunt for their next meal!🐟
This incredible feat raises a major question: how do seals withstand underwater pressure and go without breathing for so long? Let's "dive in" and learn more about the remarkable adaptations of these amazing marine mammals! 🦭
🫁Before a dive, seals will exhale, expelling most of the air out of their lungs. Their flexible ribs allow their lungs to collapse completely under water pressure, and are protected by a a slippery fluid called pulmonary surfactant to keep the tissues from sticking together. This prevents nitrogen from dissolving into the bloodstream, protecting the seal from decompression sickness.
🩸During a dive, seals rely on the high amounts of oxygen stored by the myoglobin, an oxygen-storing protein in their muscles. Marine mammals also have a larger blood volume and more hemoglobin to carry oxygen through the body than land mammals do.
🧠To conserve oxygen during a dive, their body shunts blood away from most organs except the heart, lungs, and brain.
🫀 While diving, a seal's heart rate slows to only four to six beats per minute through a process called bradycardia, helping to conserve oxygen.
👂Seals even have a special sinus in their middle ear that fills up with blood to keep their ears from popping! This also helps conduct sound vibrations directly to the inner ear, allowing seals to hear clearly underwater.
photo 📷Justin Turner-Marine Mammal Stranding Center
