12 Aquatic Creatures That Breathe Air (2025)

The boundary between aquatic and terrestrial life isn’t as clear-cut as we might imagine. While most aquatic animals extract oxygen from water through gills, a fascinating variety of creatures have evolved the ability to breathe atmospheric air. These evolutionary marvels demonstrate nature’s incredible adaptability, allowing organisms to thrive in challenging environments where oxygen levels in water may be insufficient. From prehistoric-looking lungfish to mammals that returned to the sea, these air-breathing aquatic animals represent remarkable examples of adaptation. Some use specialized organs, while others have modified their behavior to access atmospheric oxygen. This article explores 14 remarkable aquatic creatures that, despite their watery homes, depend on air to survive.

12. Lungfish Living Fossils with Primitive Lungs

Lungfish represent one of evolution’s most fascinating transitions between aquatic and terrestrial life. These remarkable fish possess both gills and primitive lungs, allowing them to breathe air when their aquatic habitats become oxygen-depleted or dry up completely. There are six extant species of lungfish distributed across three families: the Australian lungfish, four African lungfish species, and the South American lungfish. Their evolutionary significance cannot be overstated, as they’re among the closest living relatives to the organisms that first made the transition from water to land approximately 400 million years ago. The Australian lungfish (Neoceratodus forsteri) primarily uses its gills but can supplement with air breathing, while African and South American species are obligate air-breathers that will drown if denied access to surface air. During drought conditions, some lungfish species can enter a state of estivation, burrowing into mud and slowing their metabolism dramatically while breathing air through a small hole until water returns.

11. Dolphins and Whales Marine Mammals with Blowholes

Dolphins and whales represent perhaps the most well-known air-breathing aquatic animals. As mammals that evolved from terrestrial ancestors, they’ve maintained their need for atmospheric oxygen despite returning to aquatic life approximately 50 million years ago. Unlike fish, these cetaceans possess lungs rather than gills and must regularly surface to breathe. Their specialized breathing apparatus—the blowhole—is essentially a nostril that has migrated to the top of the head, allowing efficient breathing at the water’s surface with minimal body exposure. Dolphins typically breathe every 2-3 minutes, though they can hold their breath for up to 10 minutes when necessary. Larger whales can remain submerged much longer; sperm whales routinely dive for 60-90 minutes and have been recorded holding their breath for over two hours. This air-breathing requirement significantly influences cetacean behavior, sleep patterns, and migration routes. They’ve evolved numerous adaptations for efficient oxygen use, including enhanced myoglobin (an oxygen-storing protein) in their muscles and the ability to reduce blood flow to non-essential organs during deep dives.

10. Sea Turtles Reptilian Divers with Lung Adaptations

Sea turtles represent a remarkable evolutionary journey, having descended from terrestrial ancestors but adapted to primarily aquatic lives while retaining the need to breathe air. These ancient reptiles possess large, efficient lungs that allow them to make extended underwater foraging excursions. Different species demonstrate varied diving capabilities: the leatherback sea turtle (Dermochelys coriacea) can dive to depths exceeding 1,000 meters and remain submerged for up to 85 minutes, while green sea turtles (Chelonia mydas) typically stay underwater for 4-5 minutes during routine activity but can hold their breath for several hours when resting. Sea turtles have evolved multiple adaptations to enhance their diving abilities, including the capacity to slow their heart rate dramatically during submersion—a phenomenon called bradycardia—and shunt blood away from non-essential organs. Unlike many reptiles, sea turtles cannot extract oxygen from water and must surface regularly to breathe. This requirement creates vulnerability during nesting, when females must leave the relative safety of the ocean to lay eggs on land, breathing air as their ancestors did millions of years ago.

9. Manatees and Dugongs Gentle Air-Breathing Herbivores

Manatees and dugongs—collectively known as sirenians—are fully aquatic mammals that, like cetaceans, evolved from four-legged terrestrial ancestors. These gentle herbivores remain completely dependent on atmospheric oxygen, surfacing every 3-5 minutes when active, though they can hold their breath for up to 20 minutes when resting. Unlike dolphins and whales with their specialized blowholes, sirenians breathe through paired nostrils located at the end of their snouts. When surfacing, they typically expose only their nostrils, taking a quick breath before returning underwater. Their lungs extend horizontally along the back rather than vertically in the chest cavity—an adaptation that helps control buoyancy and maintain a horizontal position in the water. Manatees have developed an unusual diaphragm structure that runs along the length of their bodies, helping them control their position in the water column through breath control. This air-breathing requirement makes these animals particularly vulnerable to boat strikes, as they must regularly approach the surface in waters often busy with watercraft. Their need to breathe air also influences their distribution patterns, with manatees famously congregating near warm water springs during colder months when their metabolic rates and breathing frequency decrease.

8. Snapping Turtles Amphibious Ambush Predators

The common snapping turtle (Chelydra serpentina) and alligator snapping turtle (Macrochelys temminckii) represent fascinating examples of semi-aquatic reptiles that breathe air but spend most of their lives underwater. Unlike their sea turtle relatives, these freshwater species can extract some oxygen from water through specialized epithelial tissue in their throat and cloaca—a process called pharyngeal or cloacal respiration—but still rely primarily on their lungs for oxygen intake. This dual respiratory system allows snapping turtles to remain submerged for remarkably long periods, sometimes exceeding several hours, particularly in cold water when their metabolism slows. During winter in northern climates, snapping turtles can survive for months beneath ice-covered ponds without surfacing for air, relying on their supplementary aquatic respiration and drastically reduced metabolic needs. When actively hunting, however, they must periodically surface to breathe. Snapping turtles have developed a behavioral adaptation of floating just below the water’s surface with only their nostrils exposed, allowing them to breathe while remaining mostly concealed from both prey and predators. This air-breathing requirement influences their hunting strategy, which typically involves lying motionless on the bottom and ambushing prey, rather than active pursuit that would demand more frequent breathing.

7. Electric Eels Obligate Air Breathers

Despite their name and appearance, electric eels (Electrophorus electricus) are not true eels but rather members of the knifefish order, more closely related to catfish. These remarkable creatures, native to South American waters, have developed a critical dependency on atmospheric oxygen despite their fully aquatic lifestyle. Electric eels possess primitive lungs derived from their swim bladder, allowing them to obtain approximately 80% of their oxygen from the air. They must surface to breathe every 10 minutes on average, though this interval varies with activity level and water conditions. This air-breathing adaptation enables electric eels to thrive in oxygen-poor environments like stagnant pools and swamps during the dry season, where purely gill-breathing fish would perish. Their oral cavity contains numerous blood vessels that absorb oxygen when the eel gulps air at the surface. Interestingly, this air-breathing requirement correlates with their electrical capabilities, as generating powerful electrical discharges—up to 600 volts—demands substantial energy and oxygen. During the rainy season, when oxygen levels in water increase, electric eels still maintain their air-breathing behavior, demonstrating how deeply ingrained this adaptation has become in their physiology over millions of years of evolution in oxygen-variable environments.

6. Amphibious Fish Mudskippers and Walking Catfish

Several fish species have evolved remarkable amphibious capabilities, spending significant time out of water while breathing air. Mudskippers (family Oxudercidae) represent perhaps the most specialized of these, having developed modified gill chambers that retain water and function as primitive lung-like structures when on land. These fish can absorb oxygen through their skin and the lining of their mouths and throats when in air. Mudskippers actively leave water to feed, interact socially, and escape aquatic predators, using their muscular pectoral fins to “walk” across mudflats. They can remain out of water for extended periods, especially in humid conditions, though they must periodically return to water or wet environments to prevent desiccation. The walking catfish (Clarias batrachus) represents another remarkable air-breathing fish. Native to Southeast Asia but invasive in Florida, these catfish possess specialized suprabranchial organs—arborescent structures above their gills rich in blood vessels—that function as accessory breathing organs. This adaptation allows them to migrate overland between water bodies, sometimes traveling hundreds of meters during rainy nights. Their ability to breathe air has contributed significantly to their invasive success, as they can survive in oxygen-depleted waters and even temporarily inhabit drainage ditches and puddles that would suffocate conventional fish.

5. Marine Crocodiles Ancient Predators with Aerial Respiration

The saltwater crocodile (Crocodylus porosus) and American crocodile (Crocodylus acutus) represent apex predators that have mastered both terrestrial and marine environments while remaining obligate air-breathers. Unlike fish, these reptiles possess well-developed lungs and cannot extract oxygen from water. Saltwater crocodiles, the largest living reptiles, can remain submerged for remarkably long periods—typically 30 minutes during active hunting but up to two hours when resting. This ability stems from several specialized adaptations, including efficient oxygen storage, reduced underwater metabolism, and the capacity to shunt blood away from non-essential organs during submersion. Marine crocodiles have evolved specialized valves in their nostrils and throats that create a complete seal, preventing water intake during submersion. Their eyes and nostrils are positioned atop their snouts, allowing them to breathe while remaining almost entirely submerged—a perfect adaptation for ambush predation. Despite their aquatic proficiency, these crocodilians must return to land for various essential activities, including nesting and thermoregulation. Their air-breathing requirement significantly influences their behavior patterns, including their famous “death roll” hunting technique, which allows them to quickly subdue prey without extended underwater struggles that would deplete their oxygen reserves.

4. Diving Beetles Insects with Underwater Air Stores

Diving beetles (family Dytiscidae) have evolved fascinating adaptations for underwater life despite being fundamentally air-breathing insects. Unlike many aquatic creatures that extract oxygen directly from water, these beetles must periodically return to the surface to replenish their oxygen supply. Their most remarkable adaptation is the ability to carry an air bubble—called a plastron or physical gill—beneath their elytra (wing covers). This bubble functions not merely as an oxygen tank but as an ingenious interface between water and the beetle’s spiracles (breathing pores). As the beetle consumes oxygen from the bubble, the reduced oxygen concentration creates a gradient that actually draws dissolved oxygen from the surrounding water into the bubble. This passive diffusion system can extend underwater foraging time substantially, with some species remaining submerged for hours. Additionally, certain diving beetle species possess hydrophobic hairs on their abdomen that trap an additional air film, further extending their submersion capacity. When they eventually deplete their air supply, the beetles must surface, typically backing up to break the water’s surface with their abdomen, where they exchange gases before diving again. This air-breathing requirement significantly influences their behavior patterns, including their selection of hunting grounds relatively close to the water’s surface.

3. Sea Snakes Reptilian Specialists with Single Lungs

Sea snakes represent one of the few groups of reptiles that have adapted to fully marine lifestyles while remaining completely dependent on atmospheric oxygen. These fascinating creatures, comprising approximately 70 species, have evolved several specialized adaptations for marine air-breathing. Most notably, sea snakes possess a single elongated lung that extends nearly the entire length of their body, providing exceptional oxygen storage capacity. This adaptation allows most species to remain submerged for 30 minutes to two hours, with some capable of dives lasting up to eight hours. The nostril valves of sea snakes close tightly underwater, preventing water intake while submerged. Unlike land snakes that ventilate their lungs through rib movement, sea snakes can partially use their specialized tracheal structures to exchange some gases directly with seawater, supplementing their primary air breathing. Most sea snake species must periodically surface to breathe, creating a vulnerability during this air-breathing requirement. One remarkable exception is the yellow-bellied sea snake (Hydrophis platurus), which can absorb up to 33% of its oxygen needs through its skin when submerged, reducing surface visits. This air dependency significantly influences sea snake distribution patterns, keeping most species in relatively shallow continental shelf waters rather than the open ocean, where surface access would require excessive energy expenditure.

2. Mangrove Killifish Fish with Amphibious Capabilities

The mangrove killifish (Kryptolebias marmoratus) represents one of the most extraordinary examples of air-breathing adaptation among vertebrates. These small fish, native to mangrove ecosystems from Florida to Brazil, can survive out of water for weeks or even months at a time—an almost unparalleled feat among fish species. Their remarkable respiratory flexibility comes from multiple adaptations: they can breathe through modified gill structures while in water, but when on land, they absorb atmospheric oxygen directly through their highly vascularized skin and through the lining of their mouths and throats. During dry periods, mangrove killifish seek refuge in damp environments such as rotting logs, leaf litter, or even coconut husks, where they can remain viable until water returns. Their ability to tolerate extreme environmental fluctuations extends beyond respiration; they can endure temperatures from 12°C to 38°C and salinities from freshwater to more than twice that of normal seawater. Perhaps most remarkably, most mangrove killifish are self-fertilizing hermaphrodites—they possess both male and female reproductive organs—allowing a single fish to establish a new population when favorable conditions return. This combination of air-breathing capability and reproductive self-sufficiency makes them uniquely adapted to survive in the highly variable mangrove ecosystem, where periodic drying creates conditions that would be lethal to most fish species.

1. Aquatic Mammals Beavers, Otters, and Hippopotamuses

Several semi-aquatic mammals have evolved specialized adaptations for underwater life while maintaining their fundamental requirement for atmospheric oxygen. Beavers (Castor canadensis and Castor fiber) can remain submerged for up to 15 minutes thanks to efficient oxygen utilization, elevated myoglobin levels in muscles, and their ability to reduce heart rate during dives. Their transparent nictitating membranes allow underwater vision while their specialized lip valves can close behind their incisors, permitting them to gnaw on submerged wood without drowning. Otters demonstrate even more advanced aquatic adaptations, with sea otters (Enhydra lutris) capable of dives lasting up to 5 minutes and giant river otters (Pteronura brasiliensis) submerging for 8 minutes or more. Their dense fur, high metabolism, and specialized blood chemistry support extended underwater hunting excursions despite their air-breathing requirements. Perhaps most surprising are hippopotamuses (Hippopotamus amphibius), which despite their massive build can remain submerged for 5-6 minutes. Their nostrils, eyes, and ears are positioned atop their heads, allowing them to breathe, see, and hear while mostly submerged. Remarkably, hippos can even sleep underwater, with an involuntary reflex causing them to rise to the surface for breath without fully waking. All these mammals share a common challenge: balancing their aquatic lifestyles with the absolute requirement for atmospheric oxygen, resulting in behavioral adaptations that minimize the vulnerability experienced during breathing at the water’s surface.

Conclusion:

The diversity of air-breathing aquatic animals reveals a fascinating intersection between two worlds—water and air—showcasing evolution’s remarkable creativity in solving the challenge of oxygen acquisition. From lungfish with ancient lungs to sea snakes with elongated respiratory systems, and from amphibious fish that walk on land to massive whales that hold their breath for hours, these species demonstrate how life can adapt to extreme and fluctuating environments. Whether through modified organs, behavioral innovations, or physiological efficiencies, these creatures underscore the evolutionary importance of flexibility in respiration. Their stories blur the boundary between aquatic and terrestrial life, reminding us that survival often depends on the ability to straddle seemingly incompatible ecosystems.