[6] Sylvilagus aquaticus fossils have been identified as early as the Pleistocene epoch, according to a 1940 discovery of molar teeth found in a Missouri deposit dating back to that era.

[5] Glaciations during the Illinoian stage likely created refugia that led to the emergence of the swamp rabbit as a distinct species.

[7] It is most abundant in Alabama, Mississippi, and Louisiana, but also inhabits South Carolina, Arkansas, Tennessee, Texas, Oklahoma, Missouri, Kentucky, Illinois, Indiana, and Georgia.

[7] Swamp rabbits spend much of their time in depressions which they dig in tall grass or leaves, providing cover while they wait until the nighttime to forage.

[7] The head and back are typically dark or rusty brown or black, while the throat, ventral surface, and tail are white, and there is a cinnamon-colored ring around the eye.

[6] Swamp rabbits maintain social order through displays of dominance, and communicate directly through vocalizations such as squeaks, chirps, squeals and alert calls.

[6] Swamp rabbits are herbivorous; they eat a variety of foraged plants, including grasses, sedges, shrubs, tree bark seedlings, and twigs.

[4] A study has found that the preferred foods of S. aquaticus are savannah panicgrass (Panicum gymnocarpum), false nettle (Boehmeria cylindrica), dewberry (Rubus trivialis) and greenbrier (Smilax bona-nox).

[11] The nests in which the young are born consist of a slight depression in the earth that is filled with grasses mixed with rabbit hair.

The occurrence of embryo resorption has been seen in S. aquaticus; this loss of in-utero litters is attributed to some type of habitat disturbance such as flooding, which may cause overcrowding to occur,[11] as well as directly inducing the release of stress hormones.

[17] Even though their swimming abilities[18] lack the speed to escape a pack of hunting dogs, swamp rabbits elude pursuers by lying still in the water surrounded by brush or plant debris with only their nose visible.

[7] Swamp rabbits have several adaptations to avoid predators: cryptic coloration, "freezing", and rapid, irregular jumping patterns.

B. lepori is also known to affect the eastern cottontail,[20] and is suspected as an agent of human Brugia infections in the northeastern United States.

[22] The rabbit is hunted in its native range, both for its products (meat and fur) and for sport, which has been noted as not significantly affecting populations.