Ants possess adaptations that allow them to survive encounters with water for extended periods. While these small insects appear fragile, their biology reveals how they resist immediate drowning, unlike many other creatures.
Ant Respiration: More Than Lungs
Ants, like many other insects, breathe through a unique respiratory system that does not involve lungs. Instead, they utilize a network of small openings called spiracles, located along the sides of their bodies. These spiracles connect to a system of branching tubes known as tracheae, which directly deliver oxygen to their cells and tissues. Unlike mammals, ants do not actively pump air; oxygen enters their system through diffusion.
The Ant’s Water-Resistant Armor
An ant’s outer layer, its exoskeleton, provides a significant defense against water. This rigid external skeleton is covered with a waxy coating composed of cuticular hydrocarbons (CHCs). This waxy layer is naturally hydrophobic, meaning it repels water. The hydrophobic properties prevent water from easily adhering to the ant’s body or entering its spiracles. This allows water to bead up and roll off, protecting the ant from immediate saturation.
Surviving the Submerge: How Long Can They Last?
Ants exhibit an impressive capacity to survive underwater for extended periods. Many species can endure submersion for hours, with some observed surviving for up to 24 hours. Certain species, particularly those adapted to flood-prone environments, can last even longer, with some records indicating survival for as long as 14 days.
This ability stems from their capacity to close their spiracles, effectively sealing off their respiratory system and preventing water from entering. When submerged, ants can also significantly slow down their metabolic rate. This reduced metabolic activity allows them to conserve the oxygen already present within their bodies, requiring up to 20 times less oxygen than when active. Water temperature plays a role in their survival, as colder water generally facilitates a longer survival time by further reducing metabolic demands. This combination of spiracle closure and metabolic slowdown enables their underwater endurance.
The Real Killers: Why Ants Eventually Succumb
Despite their resilience, ants are not impervious to water and will eventually succumb. Prolonged submersion depletes their limited oxygen reserves, leading to suffocation as their internal systems can no longer function without gas exchange. Even with closed spiracles and a slowed metabolism, the available oxygen eventually runs out.
Beyond suffocation, other factors contribute to their demise. Small ants can be particularly vulnerable to the surface tension of water, which can trap them and make it difficult to escape once they fall in. This surface tension, acting like a sticky film, can prevent them from breaking free, leading to exhaustion and eventual drowning. Extreme water temperatures, whether too hot or too cold, can also overwhelm their physiological adaptations, leading to death.