Unlike other Sylvilagus in which females are slightly larger than males, there apparently is no size difference between male and female swamp rabbits. The average adult weighs over 2.2 kg (4.8 lb) with some rabbits weighing as much as 2.7 kg (6 lb).

The status of the species is a growing conservation concern in many states, particlualrly along the northern periphery of its range, because of the disappearance of much of the forested bottomlands with which this species is associated. Many of these bootomlands have been cleared for agriculture and other land uses, and the remaining bottomland is increasingly fragmented and isolated. This habitat loss has resulted in a decline in rabbit abundance and distribution throughout its

FOOD HABITS

Swamp rabbits excrete 2 kinds of fecal pellets - soft green ones and brown ones. The soft green pellets are re-ingested to maximize the nutrients gained from food. Microorganisms attach to these pellets in the gut and can increase the amount of nutrients extracted the second time around. This practice, called coprophagy, occurs mainly during the daytime while resting rather than at night when rabbits are feeding.

Swamp rabbits are crepuscular to nocturnal, being most active at dawn and dusk and during the night. They are generally solitary, associating with other swamp rabbits only during the breeding season. Swamp rabbits are territorial, unlike many other rabbits of the genus Sylvilagus. The males are vocal and demonstrate "chinning" - a pheromone marking display most noted in the European rabbit (Oryctolagus cuniculus). Vocal distress calls consist of squeals and high-pitched squeaks. Swamp rabbits are secretive and are seldom seen except when flushed from their concealed resting spot (usually a thicket or log).

Predator Avoidance

Social

There is a linear dominance hierarchy among the males and a mutual toleration among the females. The male dominance hierarchy determines the mating priority and apparently reduces fighting among reproductively active males. However, males do fight for access to estrous females during the breeding season. The alpha (most dominant) male dominates all males below him with an emphasis on his immediate subordinates and is responsible for most copulations.

Swamp rabbits are postpartum synchronous breeders with estrous generally lasting <1 hour. The synchronous estrous behavior in unbred females is on a 12-day cycle. The gestation period for swamp rabbits ranges from 35-40 days, with 36-38 days the most common. Swamp rabbits may produce up to 6 litters per year, but 2-3 is most common with the second litters generally being the largest litter.

DEVELOPMENT

At birth, the young are covered in fur but their eyes and ears are closed, unlike most other cottontails. Young rabbits open their eyes and are able to walk 2-6 days after birth, and they leave the nest 12-15 days after birth.

Juveniles reach adult weight within their first year (by about 10 months of age) with many juvenile swamp rabbits attaining adult weight by January. Juveniles born early in the year probably attain adult weight by late winter, but late-born juveniles do not attain adult weight until the following spring. The average swamp rabbit life span is estimated to be 1.8 years.

HOME RANGE

Swamp rabbits frequent a definite local range which they refuse to leave, even when pursued by dogs. Swamp rabbit home range estimates vary in size, with estimates ranging from <1 ha to 20.2 ha, depending on the location and method used to estimate the home range. There generally is extensive overlap between the home ranges of males and females and little overlap between animals of the same sex. Spring summer home ranges are larger than winter home ranges. The portion of the home range used can be influenced by water depth and season.

ECONOMIC IMPACTS FOR HUMANS

Positive

Negative

Swamp rabbits can damage crops and other vegetation important to humans if located close to a swamp or lowland area.