How Marine Mammals, Like Whales and Seals, Breathe Underwater and On Land

Contrary to the common assumption that mammals hold their breath underwater, marine mammals such as whales and seals have evolved unique physiological and behavioral mechanisms to manage their breathing both in and out of water. This article delves into the fascinating processes and adaptations that enable these creatures to survive and thrive in their aquatic environments.

The Special Adaptations of Marine Mammals

Marine mammals have several physiological adaptations that allow them to hold their breath for extended periods underwater. These adaptations include enlarged carbon dioxide (CO2) buffers in the blood and muscles, which help them store oxygen and reduce the buildup of CO2. Additionally, they have a highly efficient circulatory system that can redirect blood flow to essential organs, conserving oxygen during diving exhibitions.

How Whales Breathe Underwater and On Land

Whales, like other marine mammals, breathe air using lungs, just like humans and other land mammals. However, their respiratory system is highly specialized to meet the demands of diving to great depths for prolonged periods. When a whale surfaces, they breathe through their blowholes located on top of their heads. This design minimizes the entry of water and ensures the whale can quickly exhale and inhale the required air.

Whales have the ability to hold their breath for up to two hours, although the average dive duration is around 10 to 20 minutes. During a dive, the whale stops its heart and respiratory muscles from contracting, preventing the air in its lungs from being pushed out. When it surfaces, the whale rapidly expels the old air and takes a fresh breath, often accompanied by a powerful blast of water from the blowholes.

Seal Breathing Patterns

Like whales, seals also possess adaptations that allow them to hold their breath while underwater. Seals can stay submerged for up to 45 minutes on average, with some species capable of diving for over an hour. However, their breathing pattern is different from that of whales. Seals, when they surface, need to release the old air in their lungs before taking a fresh breath. This is because seals use a combination of blowing and swallowing to blow out excess air and create a seal around their nostrils for a tight seal when they dive.

In a typical dive sequence, seals will take a deep breath, hold it for a period, and expel the air before diving. They have a high capacity for oxygen storage in their muscles and blood, which allows them to endure long periods underwater. When they surface, they can do so quickly, thanks to their streamlined bodies and powerful flippers, which aid in rapid ascent.

Adaptations for Survival in Aquatic Environments

The ability to hold one's breath underwater is a crucial survival mechanism for marine mammals, especially in deep and cold oceanic environments. Their adaptations include:

Circulatory Redirection: Marine mammals can redirect blood flow away from non-essential organs, such as the skin, to vital organs like the brain and heart, ensuring they have sustained oxygenation. Blood Gases: Marine mammals have higher concentrations of the oxygen-binding protein, hemoglobin, in their blood, which increases their oxygen-carrying capacity. Respiratory Capacity: They have a large lung capacity, allowing them to take in more air with each breath, thereby storing more oxygen.

These adaptations enable marine mammals to thrive in environments where other mammals would not survive for extended periods. Understanding these adaptations not only enhances our appreciation of these incredible creatures but also provides valuable insights into the broader field of comparative physiology.

Conclusion

Mammals, including marine mammals like whales and seals, do not hold their breath underwater—they have evolved specialized mechanisms that allow them to manage their breathing efficiently. These adaptations not only enable them to survive in aquatic environments but also highlight the remarkable diversity of life on our planet.