Last Updated on 02/12/2024

A significant part of why marine mammals have such an impressive ability to use their lung capacity is the unique way in which they utilize oxygen, as well as their greater tidal range. These qualities, enhanced by their anatomy, which has adapted perfectly to life in the ocean, are the key components for explaining how these magnificent animals are able to safely explore even the deepest reaches of the sea.

Most marine mammals are capable of holding their breath for long periods of time. Since feeding, mating and many other activities essential to the species’ survival normally happen below the surface, this skill becomes crucial. Sea lions and cetaceans normally take only one breath per surfacing, while seals and deeper diving cetaceans sometimes spend an extended period of time at the surface. Additionally, larger whales, such as the sperm whale and bottlenose whale are able to routinely travel from the surface down to great depths, sometimes diving as deep as 6,000 feet, and proving that their oxygen stores can withstand enormous pressures and showing a resilience seldom seen in the animal kingdom.

Most people focus immediately on the ability that marine mammals have to hold their breath for longer periods of time. Although this is the goal that they are reaching for, it is also the ultimate result of many intricate, complex processes having to do with the way these creatures use oxygen in the first place. First of all, it’s important to understand that, for each breath of air taken into their lungs, marine mammals – like all breathing creatures – only receive oxygen in proportion of about 1/4. These mammals can reduce the effect of nitrogen and ensure that their oxygen levels are used far more efficiently, also featuring larger oxygen stores that are significantly greater than in the case of humans.

Deep diving whales and seals have reinforced peripheral airways, allowing the lungs to collapse during deeper dives, preventing nitrogen from being absorbed to avoid high blood nitrogen levels. There is, of course, far more to diving deep than just holding your breath. Pressure can have a powerful effect on areas of the body filled with gas, such as the inner ear or the sinuses, just as much as on the lungs. Some types of cetaceans feature an extensive venous plexus, which reduces the air cavity in the inner ear, while sinuses are enhanced through a stronger vasculature that acts in a similar way to help the mammals adapt to greater pressure.

When compared to human lung capacity usage – which is generally limited to about 8-10% while resting and 15-17% when exercising – marine mammals use up a much vaster storage amount, while also actually having larger lung capacities and more resilient lungs, meant to withstand the crushing pressures of the ocean depths. While most phocids tend to exhale before diving (seals and delphinidae generally using less than 25% of their ability to store vital oxygen while diving), creatures like the sea otter are able to maintain 75% oxygen stores. The tidal volume of marine mammals is typically larger than 75%, due mainly to their lungs’ more flexible tissue composition, more cartilage in the ribs and much greater elasticity in the recoil of their lungs, diaphragm and chest cavity, when compared to terrestrial mammals.

When you take a deep breath, filling your lungs to their capacity, it’s an invigorating moment. But did you know that we humans typically utilize only about 10% of our lung capacity with each breath? Now, consider the marine mammals – dolphins, whales, and seals, among others – who have evolved to use an astonishing 75% of their lung capacity. This remarkable adaptation isn’t just a fun fact; it’s a critical component of their survival in the vast and deep oceans where they reside.

Marine mammals have evolved exceptional physiological adaptations to thrive in their underwater environment. One of the most significant is their ability to use a large portion of their lung capacity, around 75%, compared to humans’ mere 10%. This capability is crucial for deep diving, as it allows them to store more oxygen, thereby extending their time underwater. The structure of their lungs and the distribution of their respiratory system’s blood vessels are uniquely designed to prevent the bends, a condition humans can suffer from when diving deep due to nitrogen absorption.

The efficient use of oxygen is another key adaptation in marine mammals. They have higher concentrations of myoglobin, a protein that stores oxygen in muscle tissue, allowing them to maintain their bodily functions even when deep underwater where oxygen is scarce. This adaptation, coupled with their ability to slow their heart rate to conserve oxygen, allows marine mammals to dive to great depths and remain there for extended periods, far surpassing human capabilities.

Marine mammals use sound to navigate, communicate, and locate food in the dark depths of the ocean. This ability is known as echolocation. Species like dolphins emit high-frequency clicks and listen for the echoes that bounce back from objects, allowing them to “see” with sound. Their large lung capacity plays a role here as well, as it enables them to produce powerful, long-lasting sounds necessary for communication and echolocation over vast distances underwater.

The social structures of marine mammals are complex and their large lung capacity aids in their vocalizations used for social interactions. Whales, for example, are known for their haunting songs, which can travel for miles underwater. These vocalizations are essential for maintaining social bonds, navigating, and mating rituals. The ability to use a significant portion of their lung capacity allows these animals to produce a wide range of sounds, from the deep, long calls of the blue whale to the rapid clicks of dolphins.

The large lung capacity of marine mammals is a critical survival tool. It allows them to dive deep quickly, avoiding predators or stealthily approaching prey. This ability to change depths rapidly and remain submerged for extended periods gives them a significant advantage in the predator-prey dynamics of the ocean. Their lung capacity, combined with their streamlined bodies and powerful tails, makes them adept hunters and elusive prey.

Energy conservation is vital for marine mammals, especially for those living in cold waters or those that migrate long distances. The efficient use of their lung capacity enables them to minimize energy expenditure during dives. By taking in a large volume of air and utilizing it effectively, they can reduce the frequency of surfacing for air, thus conserving energy and maximizing their time spent foraging or migrating.

Marine mammals’ ability to use 75% of their lung capacity is a fascinating adaptation that highlights the extraordinary lengths life has gone to inhabit every niche of our planet, including the deep and mysterious oceans. This remarkable feature allows these animals to dive deep, communicate effectively, hunt proficiently, and survive in the vast underwater world. Understanding these adaptations not only sheds light on the marvels of evolution but also emphasizes the importance of preserving these unique creatures and their habitats.

1. Why do marine mammals use such a large portion of their lung capacity? Marine mammals use a large portion of their lung capacity to store more oxygen, allowing them to dive deeper and stay underwater longer. This adaptation is crucial for their survival, aiding in foraging, predator avoidance, and social interactions.
2. How does the large lung capacity of marine mammals help in echolocation? The large lung capacity enables marine mammals to produce powerful sounds necessary for echolocation. These sounds travel underwater and bounce back from objects, helping the animals navigate, hunt, and communicate in the absence of light.
3. Can marine mammals suffer from the bends like humans? Marine mammals have adapted to avoid the bends, a condition caused by rapid decompression. Their unique lung structure and the way they manage nitrogen absorption and release during dives prevent the formation of harmful gas bubbles in their bloodstream.
4. How does the large lung capacity affect the social behavior of marine mammals? The ability to use a significant portion of their lung capacity allows marine mammals to produce a wide range of vocalizations. These sounds are essential for maintaining social bonds, navigating, mating rituals, and more, making their large lung capacity a key factor in their complex social interactions.
5. What role does myoglobin play in the diving capabilities of marine mammals? Myoglobin stores oxygen in muscle tissues, allowing marine mammals to maintain bodily functions even when underwater where oxygen is scarce. This high myoglobin concentration, coupled with their large lung capacity, enables these animals to dive deep and remain submerged for extended periods, enhancing their survival capabilities.