The North American Opossum (Didelphis virginiana) is a highly adaptable marsupial. While primarily terrestrial and arboreal, opossums are capable swimmers. They are not strictly aquatic, but they readily swim when necessary, using this ability as a valuable survival trait to navigate their diverse environments.
How Opossums Navigate Water
Opossums are strong swimmers, using a modified quadrupedal gait—essentially a doggy-paddle—that resembles their movement on land. This limb movement generates propulsion and keeps their nasal openings above the surface for breathing.
Their prehensile, mostly hairless tail acts like a rudder, moving side to side to help steer and maintain balance. Opossums can also engage in underwater swimming, diving and traveling short distances, up to about 15 feet, without surfacing. They demonstrate aquatic competence by controlling the closing of their nostrils.
Behavioral Drivers for Swimming
Opossums swim out of necessity, not leisure. A primary driver is predator evasion, as swimming provides a viable escape route from land-based threats like coyotes or domestic dogs. They readily enter the water to put distance between themselves and a pursuer, which is a quicker defense than feigning death.
Another reason for aquatic travel is foraging or crossing water barriers. Opossums are opportunistic omnivores and will cross small rivers, streams, or ponds to reach new feeding grounds. They navigate water to access insects, aquatic vegetation, or other small food items, expanding their feeding range or escaping flooded dens.
Opossums in Their Natural Habitat
Opossums prefer habitats close to water sources, such as streams, swamps, and marshes. While not semi-aquatic specialists, they interact with water frequently because riparian areas offer abundant food and cover.
However, opossums face risks when swimming. Prolonged swimming, especially in cold conditions, can lead to rapid exhaustion and hypothermia. This energy expenditure makes long-distance swimming rare, and large bodies of water often act as natural boundaries to their distribution. Although capable swimmers, the opossum remains primarily a terrestrial animal that uses its aquatic skill for survival and accessibility within its home range.
This diagonal sequence of limb movements is necessary to generate both forward propulsion and an upward force to keep their nasal openings above the water’s surface for breathing. The opossum’s tail, which is prehensile and mostly hairless, also plays a part in their aquatic movement. The tail moves from side to side, acting somewhat like a rudder to help steer and maintain balance while swimming. Some accounts suggest they can even engage in underwater swimming, diving and traveling short distances, up to about 15 feet, without surfacing for air. This diving ability, combined with their ability to easily control the closing of their nostrils, demonstrates a surprising level of aquatic competence.
Behavioral Drivers for Swimming
The motivation for an opossum to enter the water is generally driven by necessity rather than leisure, making it a situational behavior. One of the primary drivers is predator evasion, as swimming provides a viable escape route from land-based threats like coyotes or domestic dogs. Opossums will readily enter the water to put distance between themselves and a pursuer, a quicker defense than their famous, but involuntary, feigning death response.
Another significant reason for aquatic travel is foraging or crossing water barriers to access food sources. Opossums are opportunistic omnivores, and they will cross small rivers, streams, or ponds to reach new feeding grounds. This includes navigating water to reach areas that may contain insects, aquatic vegetation, or other small food items. Swimming is simply another form of locomotion they employ to expand their feeding range or when their den is displaced by flooding.
Opossums in Their Natural Habitat
Opossums show a distinct preference for habitats that are close to water sources, such as streams, swamps, and marshes. Although they are not classified as semi-aquatic specialists, their presence in these moist environments means they interact with water frequently. This preference is likely due to the abundance of food and cover found in riparian areas.
Despite their swimming ability, opossums face limitations and risks when in the water. Prolonged swimming, especially in cold conditions, can lead to rapid exhaustion and a shivering response, posing a risk of hypothermia. This energy expenditure and the danger of cold water make long-distance swimming rare, and large bodies of water may act as a natural boundary to their distribution. Therefore, while they are capable swimmers, the opossum remains primarily a terrestrial animal that uses its aquatic skill as a tool for survival and accessibility within its home range.