Mammal Species of the World
Click here for The American Society of Mammalogists species account
Sylvilagus aquaticus can be found in most of the south-central United States and the Gulf coast. It is abundant in Alabama, Mississippi and Louisiana. Sylvilagus aquaticus can also be found in parts of South Carolina, Tennessee, Texas, Oklahoma, Missouri, Kansas, Illinois, Indiana, and Georgia.
Biogeographic Regions: nearctic (Native )
S. a. littoralis occurs only in the southern gulf coastal section of the range. S. a. aquaticus occurs in the northern section of the range, more common in dense forest (Chapman and Feldhamer 1981, Chapman and Ceballos 1990).
endemic to a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Eastern Texas and eastern Oklahoma east to southern Indiana, western South Carolina, and Georgia.
Sylvilagus aquaticus is the largest member of its genus, the cottontails. However, its ears are smaller relative to other cottontails. The head and back are usually a mix of dark brown, rusty brown, or black. The throat, ventral surface and tail are white. A clear cinnamon-colored ring is visible around the eye. Males are slightly larger than females. Males weigh from 1816 to 2554 grams, with an average of 2235 g. Females are from 1646 to 2668 grams, averaging 2161 g.
Altricial young are born with fur up to 5 mm long with a weight of approximately 61.4 g. At birth, their fur color is dark (either brown or black) on their back, sides and throat. The tail, chin and abdomen are white. The head is a mix of tan and black. Their eyes are closed when born and open in 4 to 7 days.
Range mass: 1646 to 2668 g.
Range length: 452 to 552 mm.
Average length: 501 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Length: 54 cm
Weight: 3000 grams
Size in North America
Average: "501 mm "
Range: 452-552 mm
Range: 1,646-2,668 g
Sylvilagus aquaticus prefers to live in swampy lowlands, marshy areas, floodplains, tributaries of larger rivers, and cypress swamps. It is typically found close to water. Swamp rabbits spend the day in self-made depressions in tall grass, leaves, or anything that provides cover until their nocturnal foraging bouts.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest ; scrub forest
Wetlands: marsh ; swamp
Habitat and Ecology
S. aquaticus prefers a diet of sedges and also feeds on grasses and forbs (Chapman and Ceballos 1990).
Females have litter sizes from one to six, and produce two to five litters per year (Chapman and Ceballos 1990). Gestation is 35-40 days (Whitaker and Hamilton 1998).
Comments: Usually restricted to floodplains, bottomlands, riparian areas. Prefers mature forests. Associated with dense, brushy thickets in wooded floodplains along borders of lakes, river, and swamps. Commonly seeks water to escape danger. Nests are built in slight depressions in ground under brush piles or fallen branches, in hollow logs, or in holes along banks. Females regularly build dummy nests.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Swamp rabbits are herbivores, foraging on a variety of plant materials, including grasses, sedges, shrubs, tree bark, tree seedlings, and twigs. Helm and Chabreck (2006) found that their preferred foods include savannah panicgrass (Phanopyrun gymnocarpon), false nettle (Boehmeria cylindrica), dewberry (Rubus sieboldii) and greenbrier (Smilax bona-nox). Swamp rabbits practice coprophagy. They have two kinds of fecal matter. The first is soft and green and still had nutrients in it--this is the kind that they eat because it gives them a chance to get more nutrients out of the food. The second kind of fecal matter are dark brown/black hard pellets--they do not eat these.
Plant Foods: leaves; roots and tubers; wood, bark, or stems
Other Foods: dung
Primary Diet: herbivore (Folivore , Granivore , Lignivore); coprophage
Comments: Commonly feeds on a wide variety of plants, usually those associated with moist or wet habitats; grasses and sedges may be important.
Swamp rabbits are important prey in their native ecosystems and their herbivory influences plant communities.
Swamp rabbits are affected by several parasites which include the trematodes Hasstilesia texensis and Hasstilesia tricolor, the cestodes Cittotaenia ctenoides, Cittotaenia variabilis, Multiceps serialis, and Raillietina stilesiellacestodes, the nematodes Graphidium strigosum, Nematodirus leporis, Obeliscoides cuniculi, Parasalurus ambiguous, Trichostrongylus calcaratus, and Trichuris leporis, fleas, ticks, and mites Haemaphysalis leporis-palustris.
- trematodes Hasstilesia texensis
- trematodes Hasstilesia tricolor
- nematodes Graphidium strigosum
- nematodes Nematodirus leporis
- nematodes Obeliscoides cuniculi
- nematodes Parasalurus ambiguous
- nematodes Trichostrongylus calcaratus
- nematodes Trichuris leporis
- cestode Cittotaenia ctenoides
- cestodes Cittotaenia variabilis
- cestodes Multiceps serialis
- cestodes Raillietina stilesiellacestodes
- mites Haemaphysalis leporis-palustris
- fleas Siphonaptera)
- ticks Acari
There are few known predators of Sylvilagus aquaticus, but known predators include domestic dogs (Canis lupus familiaris), American alligators (Alligator mississippiensis), and humans (Homo sapiens). This species is the 2nd most hunted rabbit in the United States. They use a combination of cryptic coloration and "freezing" to avoid being detected and a rapid, irregular jumping pattern when fleeting to avoid capture.
- American alligators (Alligator mississippiensis)
- domestic dogs (Canis lupus familiaris)
- humans (Homo sapiens)
Anti-predator Adaptations: cryptic
Annual or seasonal home range size in different areas: about 1-5 ha (see Kjolhaug and Woolf 1988). Population density in high quality habitat may reach 2/ha or more (Kjolhaug and Woolf 1988).
Life History and Behavior
Swamp rabbits are normally not vocal except when they feel threatened. Males also leave scent marks to establish territories. Other Sylvilagus species also drum the ground with their rear feet to indicate aggression.
Communication Channels: tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
Comments: Usually active prior to sunset.
There is not much known about the wild or captive lifespans of Sylvilagus aquaticus because there have been very few studies examining this topic. Other Sylvilagus species live from 7 to 9 years maximum.
Status: wild: 10 (high) years.
Status: wild: 1.8 years.
Status: wild: 1.8 years.
Swamp rabbits are synchronous breeders; all the members of a population breed at or around the same time. Prior to breeding a predictable sequence of behaviors occurs. First, females chase and/or threaten the males. Consequently, the males dash away. A jumping sequence follows. Finally, copulation occurs, and females begin chasing the males again.
Mating System: polygynandrous (promiscuous)
Swamp rabbits usually begin breeding in mid- to late-February until August. Few exceptions are noted: in Texas, breeding occurs year round, in Louisiana, breeding can occur in every month except October.
Estrous behavior in unbred females follows a 12-day cycle, and estrus itself lasts about an hour in S. aquaticus. The gestation period lasts from 35 to 40 days (average of 36 to 37 days). They give birth to 1 to 6 offspring with an average of 3 offspring per litter.
Females make nests out of grass, dead twigs, and leaf litter above ground. These nests are typically 5.5 cm deep, 15 cm wide, and 18 cm high, and have side entrances. Sometimes, they use holes in large stumps or logs, Females also tend to build dummy nests before they build a real nest, which differs in that it is lined with fur before females give birth.
Young become sexually mature between 23 and 30 weeks old. Although juveniles are capable of breeding in their first year, most do not. Females have between 1 to 6 litters a year but 2 to 3 is most common.
Breeding interval: Females typically have 2 to 3 litters per year.
Breeding season: Breeding occurs from mid- to late-February in most places, but can occur year-round.
Range number of offspring: 1 to 6.
Average number of offspring: 3.
Range gestation period: 35 to 40 days.
Average gestation period: 36.5 days.
Range time to independence: 12 to 15 days.
Range age at sexual or reproductive maturity (female): 23 to 30 weeks.
Range age at sexual or reproductive maturity (male): 23 to 30 weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Mothers stay with their young until they leave the nest at 12 to 15 days old. She nurses them usually around dusk and dawn. The mother continues to feed the young after they leave the nest. Once the young are weaned there is no further parental care. Males do not care for young.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
Breeding season varies from late January-midsummer (peak February-March). Gestation lasts 35-40 days. Litter size is 1-6, average 2-3. First litters are smallest. Up to 5 litters may be produced per year; usually 2?
The IUCN rank of this species is Lower Risk/Least Concern. Sylvilagus aquaticus has a global rank of "Secure" from NatureServe2007. In Alabama, Georgia, Mississippi, Texas, and Louisiana populations are considered secure. Swamp rabbits are vulnerable in Kentucky and Arkansas and imperiled in Oklahoma and South Carolina.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
In Missouri, the overall area of suitable habitat is decreasing, but there are still several viable populations within the known range, and there is some indication that new populations have recently been naturally established, possibly due to dispersal facilitated by flooding (Scheibe and Henson 2003).
In Illinois, a 1995-1997 study showed a stable distribution of S. aquaticus in this range over the previous ten years (Barbour et al. 2001).
In Louisiana, there are large tracts of suitable habitat and it is an important game species (Chapman and Ceballos 1990).
In South Carolina, Rabbit Hunter Survey 2006-2007 shows that there is a decline in rabbits jumped/hour, 1.39 (2006) to 1.26 (2007) (South Carolina Rabbit Hunter Survey, 2006-2007).
Habitat loss has been the greatest cause of decline of S. aquaticus. In Missouri in 1973, a decline of suitable habitat from 850,000 ha to 40,000 ha was recorded over the previous 103 years (Korte and Fredrickson 1977). The habitat was converted from forest to cropland.
Habitat fragmentation is an issue associated with human encroachment upon S. aquaticus habitat. Many S. aquaticus populations exist on small tracts of private property, impeding dispersal and creating difficulties for management (Scheibe and Henson 2003).
Flooding of wet forested areas has a negative impact on S. aquaticus populations, but floods in some areas induce dispersal (Scheibe and Henson 2003).
Comments: Primary threat is habitat destruction/degradation.
S. aquaticus is currently found in three managed areas in Missouri: Mingo National Wildlife Refuge (NWR), Duck Creek Conservation Area, and Donaldson Point Conservation Area (Scheibe and Henson 2003). It also occurs in White River NWR in Arkansas, Panther Swamp NWR, Mathews Brake NWR, Hillside NWR, and Morgan Brake NWR in Mississippi, Atchafalaya NWR in Louisiana, Deep Fork NWR in Oklahoma, and Chickasaw NWR in Tennessee (U.S. Fish and Wildlife Service 2006).
Relevance to Humans and Ecosystems
Swamp rabbits are usually harmless, but may occasionally damage crops and other vegetation.
Negative Impacts: crop pest
Swamp rabbits are hunted for fur, meat, and for sport in the southeastern United States.
Positive Impacts: food ; body parts are source of valuable material
Comments: Commonly hunted for sport and meat.
The swamp rabbit (Sylvilagus aquaticus), or swamp hare, is a large cottontail rabbit found in the swamps and wetlands of the southern United States. Other common names for the swamp rabbit include marsh rabbit and cane-cutter. The common name, along with the species name “aquaticus” (meaning found in water), are suitable names for a species with a strong preference for wet areas and that will take to the water and swim.
Range and habitat
The swamp rabbit is found in much of the south-central United States and along the Gulf coast. It is most abundant in Alabama, Mississippi, and Louisiana, but also inhabits South Carolina, Tennessee, Texas, Oklahoma, Missouri, Kansas, Illinois, Indiana, and Georgia.
Swamp rabbits mainly live close to lowland water, often in cypress swamps, marshland, floodplain, and river tributaries. 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.
S. aquaticus is the largest of the cottontail species, although its ears are smaller than other cottontails. Males are slightly larger than females. 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. Their sides, rump, tail and feet are much more brownish, along with a pinkish-cinnamon eye-ring as opposed to the whitish eye-ring in eastern cottontails.
S. aquaticus males vary in weight from 1,816 grams (4.004 lb) to 2,554 grams (5.631 lb), with an average of 2,235 grams (4.927 lb); females vary from 1,646 grams (3.629 lb) to 2,668 grams (5.882 lb), averaging 2,161 grams (4.764 lb). S. aquaticus ranges in length from 452 millimetres (17.8 in) to 552 millimetres (21.7 in), with an average length of 501 millimetres (19.7 in).
Known predators of S. aquaticus are domestic dogs (Canis lupus familiaris), American alligators (Alligator mississippiensis), and humans (Homo sapiens). Even though their swimming abilities 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. The species is hunted for fur, meat, and sport, and is the second-most commonly hunted rabbit in the United States. Swamp rabbits have several adaptations to avoid predators: cryptic coloration, "freezing," and rapid, irregular jumping patterns.
Ontogeny and reproduction
S. aquaticus are synchronous breeders. Females give birth to altricial young. Young are born with well-developed fur but their eyes are closed and they are immobile. Their eyes have opened by day 3 and the young have begun walking. They are weaned and leave the nest after about 15 days. Young are sexually mature at 7 months and reach adult weight at 10 months. The nest in which the young are born consist of a slight depression in the earth that is filled with grasses mixed with rabbit hair.
Breeding season varies widely across the range of S. aquaticus, occurring anywhere between February and August, and can occur year round in Texas. Spermatogenesis has been noted to occur in S. aquaticus in Missouri in October and November. In a Mississippi study, groups of males harvested in December and February had the higher percentage of individuals with descended testes than those harvested in any other month (Class 2006). S. aquaticus exhibit induced ovulation and have an hour-long estrous period. The gestation period lasts 35 to 40 days. Females can have 1 to 3 litters a year with each litter consisting of 4 to 6 young. It has been documented that the occurrence of embryo resorption in seen in S. aquaticus. This loss of in-utero litters is thought to be attributed to some type of habitat disturbance such as flooding, which may cause overcrowding to occur.
Swamp rabbits are herbivorous; they eat a variety of foraged plants, including grasses, sedges, shrubs, tree bark seedlings, and twigs. They feed mainly at night but rain showers will often cause them to feed during daytime as well. A study has found that the preferred foods of S. aquaticus are savannah panicgrass (Phanopyrum gymnocarpon), false nettle (Boehmeria cylindrica), dewberry (Rubus sieboldii) and greenbrier (Smilax bona-nox).
Rival males will often engage in aggressive encounters that sometimes become violent enough to kill one of the combatants. When fighting, males will stand on their hind legs and use their teeth and claws to inflict wounds on their opponent. They will also jump from the ground and strike with the sharp claws of the hind feet.
In 1979, the swamp rabbit species enjoyed a brief stint of notoriety when one swamp rabbit had a close encounter with Jimmy Carter. In April of that year, as President Carter was fishing on a small pond on his farm, a visibly agitated swamp rabbit approached his boat and tried to board. Carter used a paddle to splash water at the rabbit to dissuade it from swimming towards the boat.
- Hoffman, R. S.; Smith, A. T. (2005). "Order Lagomorpha". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 207–8. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Smith, A.T. & Boyer, A.F. (2008). "Sylvilagus aquaticus". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved 1 February 2010.
- "Swamp Hare". New International Encyclopedia. 1905.
- Reed, Don (September 2008). "Wildlife Species Profile Swamp Rabbit ( Sylvilagus aquaticus )". Louisiana Wildlife News (5) (Louisiana State University Agricultural Center). Retrieved 25 November 2014.
- Sylvilagus aquaticus (swamp rabbit), Animal Diversity Web, University of Michigan Museum of Zoology.
- Courtney, Emily M. (5 September 2008). "Swamp rabbit ( Sylvilagus aquaticus )". Mammals in Mississippi (3) (Department of Wildlife and Fisheries, Mississippi State University). Retrieved 11 December 2014.
|Wikimedia Commons has media related to Sylvilagus aquaticus.|
Names and Taxonomy
Comments: Sylvilagus aquaticus and S. palustris share a derived karyotype (2n=38) (see Hoffmann, in Wilson and Reeder 1993).