Cottontail Rabbit (Sylvilagus spp.)
The cottontail is found throughout the eastern and Midwestern United States, and is common throughout much of its range.
The high reproductive capacity and adaptability of this species has made the cottontail one of the most important game animals in North America.
Family: Leporidae – hares, rabbits
Genus: Sylvilagus – There are approximately ten cottontail species including:
Sylvilagus floridanus – Eastern cottontail (widest distribution)
S. audubonii – Audobon’s cottontail
S. bachmani – Brush rabbit
S. palustris – Marsh rabbit
S. nuttallii – Mountain cottontail
Although distinct species, all are commonly referred to as “cottontails”.
Cottontail rabbits eat a wide variety of plant foods including grasses, sedges, sprouts, leaves, fruits, buds, and bark. During the summer months, cottontails primarily eat grasses, legumes, succulent annuals, weeds, as well as the occasional garden vegetable. The winter diet includes small grains, as well as twigs, bark, and buds of shrubs and trees.
Favorite food items often include white and crimson clover, Bahia grass, and green succulent vegetation like alfalfa, wheat, barley, ryegrass, and winter peas.
A captive diet frequently consists of a variety of greens, grasses, clover, and hay.
Cottontail rabbits serve as the “poster child” for prey species, as they serve as fair game for nearly all predators. This species tends to be high strung and easily stressed. Cottontails do not bear the rigors of captivity well and should be maintained in captivity for as short a period as possible. Provide adequate visual security like a hide box and house them as far away as possible from the sight, sound, and smell of dogs and cats.
Cottontails are solitary animals that are relatively intolerant of conspecifics.
Cottontails are also crepuscular and nocturnal. Feeding activity peaks 2 to 3 hours after dawn and during the hour after sunset.
Normal physiologic values
|Temperature||101.3-103 F||38.0-39.6 C|
|Pulse||not available (n/a)|
|Mean life span||<3 years|
|Sexual maturity||2-3 months||smaller species reach puberty earlier than larger species|
|Litter size||1-7 (average 3-4)|
|Birth weight||23-33 g|
|Eyes open||Day 4-5|
|Litter size||1-6 (average 2)|
|Weaning age||6-8 weeks|
|Emerge from nest||˜ Day 14|
|Weaning age||Day 16-22|
|Independent||Week 7-8||Eyes open, ears erect, ˜ 4 inches (10 cm) long|
|Body weight, 6 months||0.5 kg (1.1-1.2 kg)|
|Adult weight||1.76-3.37 lb (0.8-1.53 kg)||Eyes open, ears erect, ˜ 4 inches (10 cm) long|
|Target environmental temperature:||65-70°F||15.6-21.0°C|
|Target environmental humidity||30% to 50%|
|Daily h20 intake||120 ml/kg/day|
The doe creates a shallow nest made of grass and lined with fur. Here the young remain hidden by litter or leaves.
The doe cottontail may breed the same day the litter is born and may repeat the young rearing process three or four times during the breeding season. A new nest is generally constructed for each litter.
The doe’s milk is extremely rich, and the young are nursed once or twice daily for 3-5 minutes at a time.
The principles and precautions for cottontail rabbit restraint are the same as for the European rabbit, however the high-strung nature of the cottontail requires particularly swift and sure technique.
Rabbits possess a relatively lightweight, delicate skeleton paired with extremely strong, well-developed back and leg muscles. With improper restraint, rabbits that struggle or kick run the risk of a broken back or leg. Always restrain rabbits on a non-slip surface such as a large, heavy towel or pad.
Gloves and protective clothing may also be indicated due to potential zoonotic risk (see ‘Important medical conditions’ below).
Venipuncture: Collect larger volumes from the jugular vein or lateral saphenous vein. Smaller samples may be taken from the cephalic vein.
Antibiotics to Avoid
Avoid antimicrobials that attack only gram-positive bacteria such as beta-lactams.
- Lincosamide, lincomycin
- Amoxicillin, ampicillin
- Cephalosporins, clindamycin
Important medical conditions
Most rabbits presented for medical care are young, less than 1 year of age. Trauma is a common reason for presentation. Other health conditions reported in cottontail rabbits include:
- Ectoparasites like ticks, lice, mites, and especially fleas are frequently observed on cottontails rabbits (see Ectoparasite Control in Small Mammals).
- Cuterebra cutaneous myiasis (also known as “warbles” or “bots”): Large fly larvae are commonly found in the subcutaneous space of the neck and chest during warm weather months. Adult flies lay eggs on the rabbit fur, which later hatch into larvae that bore through the skin. Cuterebra larvae grow until they are approximately 1.5 inches (3.8 cm) long, at which time they emerge from the rabbit’s skin and fall off the rabbit. The larva then burrows into the ground where it pupates and later emerges as an adult fly. Mortality is rare in infected rabbits.
- Coccidiosis is found in most cottontails. Eimeria media and E. perforans can infect the intestines, potentially causing fatal enteritis in stressed juveniles. Hepatic coccidiosis is caused by E. steidae.
- Fibroma virus, a member of the poxvirus, causes Shope’s fibroma or “rabbit horn”. Disease is spread by arthropod vector. Skin lesions are occasionally seen on the legs, feet, and ears of cottontail rabbits. Lesions begin as a slight thickening of subcutaneous tissues, and progress over several months before suddenly regressing. Papillomavirus causes horny warts on the neck, shoulders, ears, or abdomen of cottontail rabbits.There is no treatment for either type of skin lesion, and both conditions usually resolve spontaneously over several months. Interestingly these viruses are a possible explanation for myths about the “jackalope”, a mythical rabbit-like creature with the antlers of an antelope. Myxomatosis causes fibrotic skin nodules and is also transmitted by arthropod vectors. Wild rabbits are generally considered quite resistant to myxoma virus, however the brush rabbit (S. bachmani) is the natural host of the North American (Californian) strains. Some cottontail species (S. nuttallii, S. audubonii) are also susceptible to South American (Brazilian) strains of myxoma virus. Unlike the disease seen in European rabbits, myxoma virus does not appear to cause disseminated disease in healthy cottontails.
- Staphylococcus aureus infection is transmitted by skin abrasion or insect bites, Infection can manifest as abscessation of lymph nodes, and can even become systemic. Diagnosed is confirmed by bacterial culture.
- Baylisascaris: Aberrant larval migration of Baylisascaris procyonis, B. columnaris has been associated with central nervous system disease (circling, loss of balance, blindness) in cottontail rabbits. Diagnosis is typically made by histopathology of the spinal cord.
Cottontail rabbits can also serve as asymptomatic carriers or intermediate hosts of a number of infectious organisms including Sarcocystis falcatula, Taenia pisiformis, Francisella tularensis (tularemia or “rabbit fever”), Listeria monocytogenes, Pasteurella spp., Yersinia spp., Leptospira spp., and Rickettsia rickettsia (Rocky Mountain spotted fever).
These conditions are very unlikely to be responsible for admission for medical care, however gloves and protective clothing should ideally be worn when handling injured rabbits since they can serve as potential reservoirs of disease.
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