Sharks, creatures adapted to life beneath the ocean’s surface, face immediate and complex challenges when removed from their aquatic environment. While popular perception might suggest an instant demise, their ability to endure out of water is more varied, depending on several biological factors and external conditions. The reality of their survival time on land is a nuanced topic rooted in their specialized physiology.
The Primary Challenge: Respiration
Sharks breathe by extracting dissolved oxygen from water as it passes over their gills. Their gills are delicate structures with numerous filaments that provide a large surface area for gas exchange. When a shark is removed from water, these filaments collapse, significantly reducing the surface area available for oxygen absorption, similar to how human lungs would struggle to function underwater.
Sharks employ two main methods for moving water over their gills. Many active, pelagic species, like great white sharks and mako sharks, rely on “ram ventilation,” meaning they must swim continuously with their mouths open to force water over their gills. If these sharks stop moving, they essentially suffocate.
Other species, particularly bottom dwellers such as nurse sharks, use “buccal pumping,” actively drawing water into their mouths and pumping it over their gills, which allows them to breathe while stationary. Some species can even switch between both methods.
Other Biological Limitations
Beyond the immediate respiratory crisis, sharks face several other biological limitations on land. Their bodies are adapted to the buoyancy of water, which supports their weight. Without this support, gravity can cause larger sharks’ internal organs to be crushed by their own body mass. This effect is more pronounced in bigger individuals, contributing to their generally shorter survival times out of water.
Sharks also experience rapid desiccation, or drying out, of their skin and delicate gill tissues when exposed to air. This loss of moisture can quickly compromise their physiological functions.
As cold-blooded animals, sharks struggle to regulate their body temperature outside of water, making them susceptible to overheating or hypothermia depending on the ambient conditions. The surrounding air temperature significantly impacts a shark’s metabolism and overall activity levels when out of water.
Factors Influencing Time on Land
Species-specific adaptations play a significant role. For instance, some bottom-dwelling sharks with buccal pumping capabilities, such as nurse sharks, are more tolerant of low oxygen conditions and can survive longer than active, ram-ventilating species. Certain species, like the epaulette shark, possess unique physiological traits that allow them to endure prolonged periods of low oxygen.
Size also influences survival time. Smaller sharks may be more susceptible to desiccation due to a higher surface area-to-volume ratio, but they are less affected by crushing body weight compared to larger sharks. Larger species, such as the great white, often succumb more quickly due to the immense pressure of their own weight on their organs.
Environmental conditions, including air temperature and humidity, further affect survival; cooler, more humid conditions can extend a shark’s time out of water. A shark’s stress level or any injuries sustained during capture or stranding can also significantly reduce its ability to survive.
Observed Survival Durations
Most shark species can survive for only a few minutes to a couple of hours when removed from water. Large sharks, for example, might only last for 15 to 30 minutes.
However, some resilient species have evolved specific adaptations that allow them to endure longer periods.
The epaulette shark (Hemiscyllium ocellatum), found in shallow tidal pools, is a notable example, capable of surviving for several hours, sometimes up to three hours, with little or no oxygen. This species can even “walk” on its pectoral fins across land to move between pools, demonstrating a remarkable tolerance for out-of-water conditions. While no shark can survive long-term out of water, these observed durations highlight the diverse physiological adaptations among different shark species.