Ants, tiny inhabitants of almost every terrestrial environment, possess adaptations that allow them to endure conditions many organisms cannot. Among these abilities is their capacity to survive periods of submergence. This biological resilience reveals mechanisms that protect them from drowning.
How Ants Survive Submerged
Individual ants employ physical and physiological adaptations to survive when submerged. Unlike humans, ants breathe through tiny openings along their bodies called spiracles. When underwater, ants can close these spiracles, effectively sealing off their respiratory system and preventing water from entering. This “breath-holding” ability is a defense against drowning.
An ant’s outer covering, its exoskeleton, is naturally hydrophobic, meaning it repels water. This water-repellent surface allows ants to trap a thin layer of air around their bodies when submerged. This trapped air acts like a miniature scuba tank, providing a temporary supply of oxygen. Ants can also significantly lower their metabolic rate, entering a torpor-like state. Their oxygen demand decreases dramatically, allowing them to conserve the limited air supply for extended periods.
Factors Influencing Underwater Endurance
The duration an ant can survive underwater is influenced by environmental and biological factors. Water temperature plays a role, as colder water generally prolongs survival times. This is because lower temperatures reduce an ant’s metabolic rate, slowing down its oxygen consumption. Colder water can also hold more dissolved oxygen, though the primary advantage comes from metabolic slowdown.
The specific ant species also influences its underwater endurance. While some ant species might only survive for a few hours when submerged, others exhibit resilience, enduring for up to 14 days. Species that naturally inhabit flood-prone regions, such as wetlands or coastlines, tend to have evolved greater capabilities for surviving prolonged submergence. The depth and duration of the submergence event are also important, as prolonged exposure can eventually overwhelm these natural defenses.
Ants’ Collective Water Survival
Beyond individual physiological adaptations, some ant species exhibit collective behaviors to survive flooding. Fire ants, particularly Solenopsis invicta, are known for their ability to form living “ant rafts.” When their underground nests are inundated, worker ants rapidly link together using their legs and mandibles. This cooperative action creates a buoyant, self-assembling structure that floats on the water’s surface.
These rafts are waterproof assemblies that protect the entire colony. The ants’ tightly interlocked bodies and their water-repellent exoskeletons create a barrier that prevents water from penetrating the raft. Within this living mat, the queen and developing brood are housed, shielded from the water below. Fire ant rafts can remain afloat for weeks, with ants at the bottom periodically rotating to the top to access air until they reach dry land.