How Some Animals Hold Their Breath for Over an Hour Underwater

For most people, holding their breath for more than a minute is a challenge. Yet some animals can remain underwater for over an hour without taking another breath. Their secret is not unusually large lungs alone, but a remarkable biological adaptation hidden inside their muscles. These animals produce exceptionally high levels of a protein called myoglobin, which stores oxygen and releases it gradually when needed. This allows them to keep swimming, hunting and diving long after the oxygen in their lungs has been used. It is one of the most impressive survival strategies in the natural world and continues to inspire scientific research into human health and endurance.

Animals That Store Oxygen in Their Muscles

The Role of Myoglobin

Unlike haemoglobin, which carries oxygen through the bloodstream, myoglobin stores oxygen directly inside muscle cells. It acts as an internal oxygen reserve, supplying muscles when fresh air is unavailable.

Marine mammals possess far greater concentrations of myoglobin than humans. Their muscles are often so rich in the protein that they appear much darker than those of land mammals.

This adaptation enables them to continue working efficiently even during prolonged dives beneath the ocean's surface.

Seals Are Masters of Breath-Holding

Among the most impressive examples are elephant seals and Weddell seals. These mammals spend much of their lives underwater searching for fish and squid.

Elephant seals can dive for more than 90 minutes and reach depths exceeding 1,500 metres. Weddell seals regularly remain submerged for over an hour while hunting beneath Antarctic sea ice.

Their extraordinary oxygen stores, combined with slower heart rates during dives, allow them to conserve energy while ensuring vital organs continue receiving enough oxygen.

Without these adaptations, such deep and lengthy dives would be impossible.

Whales and Dolphins Use the Same Strategy

Whales are also equipped with exceptionally high myoglobin levels. Sperm whales, famous for hunting giant squid in the deep ocean, can dive for well over an hour and descend to depths of more than 2,000 metres.