Swamp rabbit

The swamp rabbit (Sylvilagus aquaticus), or swamp hare,[4] 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 species has a strong preference for wet areas, and it will take to the water and swim.[5]

Swamp rabbit[1]
Temporal range: Pleistocene–recent[2]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Lagomorpha
Family: Leporidae
Genus: Sylvilagus
Species:
S. aquaticus
Binomial name
Sylvilagus aquaticus
(Bachman, 1837)
Swamp rabbit range

Range and habitat

The swamp rabbit is found in much of the south-central United States and along the Gulf coast.[6] It is most abundant in Alabama, Mississippi, and Louisiana, but also inhabits South Carolina, Tennessee, Texas, Oklahoma, Arkansas, Missouri, Kansas, Kentucky, Illinois, Indiana, and Georgia.[6]

Swamp rabbits mainly live close to lowland water, often in cypress swamps, marshland, floodplain, and river tributaries.[6] 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.[6]

There is concern that swamp rabbits are increasingly becoming exposed to predation, especially during snowy/wintry seasons. Snow cover has shown to increase swamp rabbit mortality by almost two times in the northern extent of their range. This is due mostly to the fact that snow cover constrains hiding ability and availability of food resources.[7]

Physical description

S. aquaticus is the largest of the cottontail species, although its ears are smaller than of other cottontails.[6] Males are slightly larger than females.[6] 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] 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.[5]

S. aquaticus males vary in weight from approximately 4 lb (1.8 kg) to 5.6 lb (2.5 kg), with an average of about 5 lb (2.3 kg); females vary from approx. 3.6 lb (1.6 kg) to 5.9 lb (2.7 kg), averaging about 4.8 lb (2.2 kg). S. aquaticus ranges in length from approx. 17.8 inches (45 cm) to 21.7 in (55 cm), with an average length of about 19.7 in (50 cm).[6]

Predation

Known predators of Sylvilagus aquaticus are domestic dogs (Canis lupus familiaris), American alligators (Alligator mississippiensis), and humans (Homo sapiens).[6] Even though their swimming abilities[8] 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.[5] The species is hunted for fur, meat, and sport, and is the second-most commonly hunted rabbit in the United States.[6] Swamp rabbits have several adaptations to avoid predators: cryptic coloration, "freezing", and rapid, irregular jumping patterns.[6]

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 three and the young have begun walking. They are weaned and leave the nest after about 15 days. Young are sexually mature at seven months and reach adult weight at 10 months.[9] 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.[5]

Breeding season varies widely across the range of S. aquaticus, usually occurring anywhere between February and August, but 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 higher percentages of individuals with descended testes than those harvested in any other months (Class 2006). S. aquaticus exhibit induced ovulation and have an hour-long estrus. 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. 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.[9]

Diet

Swamp rabbits are herbivorous; they eat a variety of foraged plants, including grasses, sedges, shrubs, tree bark seedlings, and twigs.[6] They feed mainly at night but rain showers will often cause them to feed during daytime as well.[5] A study has found that the preferred foods of S. aquaticus are savannah panicgrass (Phanopyrum gymnocarpon), false nettle (Boehmeria cylindrica), dewberry (Rubus trivialis) and greenbrier (Smilax bona-nox).[6]

Like other lagomorphs, they have a double digestion. Food passes through their gut twice, first producing soft, green feces (cecotropes) which still contain nutrients. These are eaten by the animal (coprophagy), and after further digestion the remains form drier, dark brown or black hard pellets, which are not eaten.[6]

Species competition

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.[5]

See also

References
  1. Hoffman, R.S.; Smith, A.T. (2005). "Order Lagomorpha". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 207–8. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. "Sylvilagus aquaticus (swamp rabbit)". PBDB.
  3. Lanier, H.C. & Nielsen, C. (2019). "Swamp rabbit". IUCN Red List of Threatened Species. 2019: e.T41296A45190578. Retrieved 2 May 2020.
  4. Gilman, D. C.; Peck, H. T.; Colby, F. M., eds. (1905). "Swamp Hare" . New International Encyclopedia (1st ed.). New York: Dodd, Mead.
  5. Reed, Don (September 2008). "Wildlife Species Profile Swamp Rabbit (Sylvilagus aquaticus)" (PDF). Louisiana Wildlife News (5). Louisiana State University Agricultural Center. Retrieved 25 November 2014.
  6. Sylvilagus aquaticus (swamp rabbit), Animal Diversity Web, University of Michigan Museum of Zoology.
  7. Hillard, Elizabeth M., et al. “Winter Snow Cover Increases Swamp Rabbit (Sylvilagus Aquaticus) Mortality at the Northern Extent of Their Range.” Mammalian Biology, vol. 93, 2018, pp. 93–96., doi:10.1016/j.mambio.2018.09.001.
  8. https://www.cbc.ca/player/play/1463046723738
  9. Courtney, Emily M. (5 September 2008). "Swamp rabbit (Sylvilagus aquaticus)" (PDF). Mammals in Mississippi (3). Department of Wildlife and Fisheries, Mississippi State University. Retrieved 11 December 2014.
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