The capybara is the world’s largest living rodent, native to South America. Thriving near abundant water sources like rivers, swamps, and lakes, capybaras are classified as semi-aquatic because they spend a significant portion of their lives moving between land and water. They are also a highly social species, often observed living in large groups near watery habitats.
Maximum Submergence Time
The capybara can hold its breath for an extended period when submerged. Scientific observations indicate this rodent can remain completely underwater for up to five minutes. This maximum duration is a survival mechanism, typically reserved for moments of extreme duress or evasion.
During routine activities, voluntary dives are much shorter, usually lasting between 30 seconds and one minute. This allows them to quickly cross a channel or briefly escape a perceived threat.
Behavioral Reasons for Diving
The primary motivation for a capybara to submerge itself is to escape danger. They are prey for large predators like jaguars, caimans, and anacondas. When threatened, the capybara quickly plunges into the water, often hiding completely submerged to avoid detection. It can then stay underwater, keeping only its nostrils exposed above the surface to breathe discreetly.
Diving is also important for thermoregulation, helping the animal manage its body temperature in hot, humid climates. During the hottest parts of the day, capybaras will wallow or remain partially submerged to cool their bodies. They also dive to feed on various aquatic plants, which form a small part of their primarily grass-based diet.
Physical Adaptations for Aquatic Life
The capybara’s anatomy is structured to facilitate its semi-aquatic lifestyle. A distinctive feature is the high placement of its eyes, ears, and nostrils on top of its large, blunt head. This arrangement allows the animal to remain almost entirely submerged while keeping its sensory organs above the waterline, enabling it to breathe and observe its surroundings.
For effective movement in the water, the capybara has slightly webbed feet. The short webbing between its toes provides an increased surface area, functioning like a paddle to propel the rodent efficiently through the water.
Physiologically, the capybara exhibits a mammalian diving reflex that helps conserve oxygen during prolonged submergence. This reflex involves a temporary slowing of the heart rate, known as bradycardia. Blood flow is redirected away from the limbs and towards the heart and brain, ensuring a steady oxygen supply during the five-minute maximum dive.